diff --git a/amalgamate.py b/amalgamate.py
index cd658268..3aa7992b 100644
--- a/amalgamate.py
+++ b/amalgamate.py
@@ -9,7 +9,7 @@ pipeline = [
 	["config.h", "export.h", "common.h", "memory.h", "vector.h", "str.h", "tuplelist.h", "namedict.h", "error.h", "lexer.h"],
 	["obj.h", "dict.h", "codeobject.h", "frame.h"],
 	["gc.h", "vm.h", "ceval.h", "expr.h", "compiler.h", "repl.h"],
-	["_generated.h", "cffi.h", "bindings.h", "iter.h", "base64.h", "random.h", "re.h", "linalg.h", "easing.h", "io.h"],
+	["_generated.h", "cffi.h", "bindings.h", "iter.h", "base64.h", "collections.h", "random.h", "re.h", "linalg.h", "easing.h", "io.h"],
 	["pocketpy.h", "pocketpy_c.h"]
 ]
 
diff --git a/include/pocketpy/collections.h b/include/pocketpy/collections.h
new file mode 100644
index 00000000..446f9da5
--- /dev/null
+++ b/include/pocketpy/collections.h
@@ -0,0 +1,13 @@
+#pragma once
+
+#include "obj.h"
+#include "common.h"
+#include "memory.h"
+#include "str.h"
+#include "iter.h"
+#include "cffi.h"
+
+namespace pkpy
+{
+    void add_module_collections(VM *vm);
+} // namespace pkpy
\ No newline at end of file
diff --git a/include/pocketpy/common.h b/include/pocketpy/common.h
index c82265dc..555aabba 100644
--- a/include/pocketpy/common.h
+++ b/include/pocketpy/common.h
@@ -21,6 +21,7 @@
 #include <type_traits>
 #include <random>
 #include <bitset>
+#include <deque>
 
 #define PK_VERSION				"1.2.7"
 
diff --git a/include/pocketpy/pocketpy.h b/include/pocketpy/pocketpy.h
index 81498d21..1748b0c3 100644
--- a/include/pocketpy/pocketpy.h
+++ b/include/pocketpy/pocketpy.h
@@ -13,6 +13,7 @@
 #include "re.h"
 #include "random.h"
 #include "bindings.h"
+#include "collections.h"
 
 namespace pkpy {
 
diff --git a/include/pocketpy/vm.h b/include/pocketpy/vm.h
index 90e64c5d..8493e51f 100644
--- a/include/pocketpy/vm.h
+++ b/include/pocketpy/vm.h
@@ -360,6 +360,7 @@ public:
     void TypeError(const Str& msg){ _error("TypeError", msg); }
     void IndexError(const Str& msg){ _error("IndexError", msg); }
     void ValueError(const Str& msg){ _error("ValueError", msg); }
+    void RuntimeError(const Str& msg){ _error("RuntimeError", msg); }
     void ZeroDivisionError(const Str& msg){ _error("ZeroDivisionError", msg); }
     void ZeroDivisionError(){ _error("ZeroDivisionError", "division by zero"); }
     void NameError(StrName name){ _error("NameError", fmt("name ", name.escape() + " is not defined")); }
diff --git a/python/collections.py b/python/collections.py
index 75d99567..9a6571df 100644
--- a/python/collections.py
+++ b/python/collections.py
@@ -1,110 +1,110 @@
-class _LinkedListNode:
-    def __init__(self, prev, next, value) -> None:
-        self.prev = prev
-        self.next = next
-        self.value = value
+# class _LinkedListNode:
+#     def __init__(self, prev, next, value) -> None:
+#         self.prev = prev
+#         self.next = next
+#         self.value = value
 
-class deque:
-    def __init__(self, iterable=None) -> None:
-        self.head = _LinkedListNode(None, None, None)
-        self.tail = _LinkedListNode(None, None, None)
-        self.head.next = self.tail
-        self.tail.prev = self.head
-        self.size = 0
-        if iterable is not None:
-            for value in iterable:
-                self.append(value)
+# class deque:
+#     def __init__(self, iterable=None) -> None:
+#         self.head = _LinkedListNode(None, None, None)
+#         self.tail = _LinkedListNode(None, None, None)
+#         self.head.next = self.tail
+#         self.tail.prev = self.head
+#         self.size = 0
+#         if iterable is not None:
+#             for value in iterable:
+#                 self.append(value)
 
-    def __getitem__(self, index):
-        assert 0 <= index < len(self)
-        node = self.head.next
-        for _ in range(index):
-            node = node.next
-        return node.value
+#     def __getitem__(self, index):
+#         assert 0 <= index < len(self)
+#         node = self.head.next
+#         for _ in range(index):
+#             node = node.next
+#         return node.value
     
-    def __setitem__(self, index, value):
-        assert 0 <= index < len(self)
-        node = self.head.next
-        for _ in range(index):
-            node = node.next
-        node.value = value
+#     def __setitem__(self, index, value):
+#         assert 0 <= index < len(self)
+#         node = self.head.next
+#         for _ in range(index):
+#             node = node.next
+#         node.value = value
 
-    def __delitem__(self, index):
-        assert 0 <= index < len(self)
-        node = self.head.next
-        for _ in range(index):
-            node = node.next
-        node.prev.next = node.next
-        node.next.prev = node.prev
-        self.size -= 1
+#     def __delitem__(self, index):
+#         assert 0 <= index < len(self)
+#         node = self.head.next
+#         for _ in range(index):
+#             node = node.next
+#         node.prev.next = node.next
+#         node.next.prev = node.prev
+#         self.size -= 1
 
-    def clear(self):
-        self.head.next = self.tail
-        self.tail.prev = self.head
-        self.size = 0
+#     def clear(self):
+#         self.head.next = self.tail
+#         self.tail.prev = self.head
+#         self.size = 0
 
-    def extend(self, iterable):
-        for value in iterable:
-            self.append(value)
+#     def extend(self, iterable):
+#         for value in iterable:
+#             self.append(value)
 
-    def append(self, value):
-        node = _LinkedListNode(self.tail.prev, self.tail, value)
-        self.tail.prev.next = node
-        self.tail.prev = node
-        self.size += 1
+#     def append(self, value):
+#         node = _LinkedListNode(self.tail.prev, self.tail, value)
+#         self.tail.prev.next = node
+#         self.tail.prev = node
+#         self.size += 1
     
-    def appendleft(self, value):
-        node = _LinkedListNode(self.head, self.head.next, value)
-        self.head.next.prev = node
-        self.head.next = node
-        self.size += 1
+#     def appendleft(self, value):
+#         node = _LinkedListNode(self.head, self.head.next, value)
+#         self.head.next.prev = node
+#         self.head.next = node
+#         self.size += 1
 
-    def pop(self):
-        assert self.size > 0
-        node = self.tail.prev
-        node.prev.next = self.tail
-        self.tail.prev = node.prev
-        self.size -= 1
-        return node.value
+#     def pop(self):
+#         assert self.size > 0
+#         node = self.tail.prev
+#         node.prev.next = self.tail
+#         self.tail.prev = node.prev
+#         self.size -= 1
+#         return node.value
     
-    def popleft(self):
-        assert self.size > 0
-        node = self.head.next
-        node.next.prev = self.head
-        self.head.next = node.next
-        self.size -= 1
-        return node.value
+#     def popleft(self):
+#         assert self.size > 0
+#         node = self.head.next
+#         node.next.prev = self.head
+#         self.head.next = node.next
+#         self.size -= 1
+#         return node.value
     
-    def copy(self):
-        new_list = deque()
-        for value in self:
-            new_list.append(value)
-        return new_list
+#     def copy(self):
+#         new_list = deque()
+#         for value in self:
+#             new_list.append(value)
+#         return new_list
     
-    def __len__(self):
-        return self.size
+#     def __len__(self):
+#         return self.size
     
-    def __iter__(self):
-        node = self.head.next
-        while node is not self.tail:
-            yield node.value
-            node = node.next
+#     def __iter__(self):
+#         node = self.head.next
+#         while node is not self.tail:
+#             yield node.value
+#             node = node.next
 
-    def __repr__(self) -> str:
-        a = list(self)
-        return f"deque({a})"
+#     def __repr__(self) -> str:
+#         a = list(self)
+#         return f"deque({a})"
     
-    def __eq__(self, __o: object) -> bool:
-        if not isinstance(__o, deque):
-            return False
-        if len(self) != len(__o):
-            return False
-        t1, t2 = self.head.next, __o.head.next
-        while t1 is not self.tail:
-            if t1.value != t2.value:
-                return False
-            t1, t2 = t1.next, t2.next
-        return True
+#     def __eq__(self, __o: object) -> bool:
+#         if not isinstance(__o, deque):
+#             return False
+#         if len(self) != len(__o):
+#             return False
+#         t1, t2 = self.head.next, __o.head.next
+#         while t1 is not self.tail:
+#             if t1.value != t2.value:
+#                 return False
+#             t1, t2 = t1.next, t2.next
+#         return True
 
 def Counter(iterable):
     a = {}
diff --git a/src/collections.cpp b/src/collections.cpp
new file mode 100644
index 00000000..d5d1f17c
--- /dev/null
+++ b/src/collections.cpp
@@ -0,0 +1,586 @@
+#include "pocketpy/collections.h"
+namespace pkpy
+{
+    struct PyDequeIter // Iterator for the deque type
+    {
+        PY_CLASS(PyDequeIter, builtins, "_deque_iterator")
+        PyObject *ref;
+        bool is_reversed;
+        std::deque<PyObject *>::iterator begin, end, current;
+        std::deque<PyObject *>::reverse_iterator rbegin, rend, rcurrent;
+        PyDequeIter(PyObject *ref, std::deque<PyObject *>::iterator begin, std::deque<PyObject *>::iterator end)
+            : ref(ref), begin(begin), end(end), current(begin)
+        {
+            this->is_reversed = false;
+        }
+        PyDequeIter(PyObject *ref, std::deque<PyObject *>::reverse_iterator rbegin, std::deque<PyObject *>::reverse_iterator rend)
+            : ref(ref), rbegin(rbegin), rend(rend), rcurrent(rbegin)
+        {
+            this->is_reversed = true;
+        }
+        void _gc_mark() const { PK_OBJ_MARK(ref); }
+        static void _register(VM *vm, PyObject *mod, PyObject *type);
+    };
+    void PyDequeIter::_register(VM *vm, PyObject *mod, PyObject *type)
+    {
+        // Iterator for the deque type
+        vm->_all_types[PK_OBJ_GET(Type, type)].subclass_enabled = false;
+        vm->bind_notimplemented_constructor<PyDequeIter>(type);
+
+        vm->bind__iter__(PK_OBJ_GET(Type, type), [](VM *vm, PyObject *obj)
+                         { return obj; });
+        vm->bind__next__(PK_OBJ_GET(Type, type), [](VM *vm, PyObject *obj)
+                         {
+            PyDequeIter& self = _CAST(PyDequeIter&, obj);
+            if(self.is_reversed){
+                if(self.rcurrent == self.rend) return vm->StopIteration;
+                PyObject* ret = *self.rcurrent;
+                ++self.rcurrent;
+                return ret;
+            }
+            else{
+                if(self.current == self.end) return vm->StopIteration;
+                PyObject* ret = *self.current;
+                ++self.current;
+                return ret;
+            } });
+    }
+    struct PyDeque
+    {
+        PY_CLASS(PyDeque, collections, deque);
+        PyDeque(VM *vm, PyObject *iterable, PyObject *maxlen); // constructor
+        // PyDeque members
+        std::deque<PyObject *> dequeItems;
+        int maxlen = -1;                                                  // -1 means unbounded
+        bool bounded = false;                                             // if true, maxlen is not -1
+        void insertObj(bool front, bool back, int index, PyObject *item); // insert at index, used purely for internal purposes: append, appendleft, insert methods
+        PyObject *popObj(bool front, bool back, PyObject *item, VM *vm);  // pop at index, used purely for internal purposes: pop, popleft, remove methods
+        int findIndex(VM *vm, PyObject *obj, int start, int stop);        // find the index of the given object in the deque
+        std::stringstream getRepr(VM *vm, PyObject* thisObj);                                // get the string representation of the deque
+        // Special methods
+        static void _register(VM *vm, PyObject *mod, PyObject *type); // register the type
+        void _gc_mark() const;                                        // needed for container types, mark all objects in the deque for gc
+    };
+    void PyDeque::_register(VM *vm, PyObject *mod, PyObject *type)
+    {
+        vm->bind(type, "__new__(cls, iterable=None, maxlen=None)",
+                 [](VM *vm, ArgsView args)
+                 {
+                     Type cls_t = PK_OBJ_GET(Type, args[0]);
+                     PyObject *iterable = args[1];
+                     PyObject *maxlen = args[2];
+                     return vm->heap.gcnew<PyDeque>(cls_t, vm, iterable, maxlen);
+                 });
+        // gets the item at the given index, if index is negative, it will be treated as index + len(deque)
+        // if the index is out of range, IndexError will be thrown --> required for [] operator
+        vm->bind(type, "__getitem__(self, index) -> PyObject",
+                 [](VM *vm, ArgsView args)
+                 {
+                     PyDeque &self = _CAST(PyDeque &, args[0]);
+                     int index = CAST(int, args[1]);
+                     index = vm->normalized_index(index, self.dequeItems.size()); // error is handled by the vm->normalized_index
+                     return self.dequeItems.at(index);
+                 });
+        // sets the item at the given index, if index is negative, it will be treated as index + len(deque)
+        // if the index is out of range, IndexError will be thrown --> required for [] operator
+        vm->bind(type, "__setitem__(self, index, newValue) -> None",
+                 [](VM *vm, ArgsView args)
+                 {
+                     PyDeque &self = _CAST(PyDeque &, args[0]);
+                     int index = CAST(int, args[1]);
+                     PyObject *newValue = args[2];
+                     index = vm->normalized_index(index, self.dequeItems.size()); // error is handled by the vm->normalized_index
+                     self.dequeItems.at(index) = newValue;
+                     return vm->None;
+                 });
+        // erases the item at the given index, if index is negative, it will be treated as index + len(deque)
+        // if the index is out of range, IndexError will be thrown --> required for [] operator
+        vm->bind(type, "__delitem__(self, index) -> None",
+                 [](VM *vm, ArgsView args)
+                 {
+                     PyDeque &self = _CAST(PyDeque &, args[0]);
+                     int index = CAST(int, args[1]);
+                     index = vm->normalized_index(index, self.dequeItems.size()); // error is handled by the vm->normalized_index
+                     self.dequeItems.erase(self.dequeItems.begin() + index);
+                     return vm->None;
+                 });
+        // returns the length of the deque
+        vm->bind(type, "__len__(self) -> int",
+                 [](VM *vm, ArgsView args)
+                 {
+                     PyDeque &self = _CAST(PyDeque &, args[0]);
+                     return VAR(self.dequeItems.size());
+                 });
+        // returns an iterator for the deque
+        vm->bind(type, "__iter__(self) -> deque_iterator",
+                 [](VM *vm, ArgsView args)
+                 {
+                     PyDeque &self = _CAST(PyDeque &, args[0]);
+                     return vm->heap.gcnew<PyDequeIter>(
+                         PyDequeIter::_type(vm), args[0],
+                         self.dequeItems.begin(), self.dequeItems.end());
+                 });
+        // returns a string representation of the deque
+        vm->bind(type, "__repr__(self) -> str",
+                 [](VM *vm, ArgsView args)
+                 {
+                     PyDeque &self = _CAST(PyDeque &, args[0]);
+                     std::stringstream ss = self.getRepr(vm, args[0]);
+                     return VAR(ss.str());
+                 });
+        // returns a string representation of the deque
+        vm->bind(type, "__str__(self) -> str",
+                 [](VM *vm, ArgsView args)
+                 {
+                     PyDeque &self = _CAST(PyDeque &, args[0]);
+                     std::stringstream ss = self.getRepr(vm, args[0]);
+                     return VAR(ss.str());
+                 });
+        // enables comparison between two deques, == and != are supported
+        vm->bind(type, "__eq__(self, other) -> bool",
+                 [](VM *vm, ArgsView args)
+                 {
+                     PyDeque &self = _CAST(PyDeque &, args[0]);
+                     PyDeque &other = _CAST(PyDeque &, args[1]);
+                     if (self.dequeItems.size() != other.dequeItems.size()) // trivial case
+                         return VAR(false);
+                     for (int i = 0; i < self.dequeItems.size(); i++)
+                         if (!vm->py_equals(self.dequeItems[i], other.dequeItems[i]))
+                             return VAR(false);
+                     return VAR(true);
+                 });
+        // clear the deque
+        vm->bind(type, "clear(self) -> None",
+                 [](VM *vm, ArgsView args)
+                 {
+                     PyDeque &self = _CAST(PyDeque &, args[0]);
+                     self.dequeItems.clear();
+                     return vm->None;
+                 });
+        // extend the deque with the given iterable
+        vm->bind(type, "extend(self, iterable) -> None",
+                 [](VM *vm, ArgsView args)
+                 {
+                     auto _lock = vm->heap.gc_scope_lock(); // locking the heap
+                     PyDeque &self = _CAST(PyDeque &, args[0]);
+                     PyObject *it = vm->py_iter(args[1]); // strong ref
+                     PyObject *obj = vm->py_next(it);
+                     while (obj != vm->StopIteration)
+                     {
+                         self.insertObj(false, true, -1, obj);
+                         obj = vm->py_next(it);
+                     }
+                     return vm->None;
+                 });
+        // append at the end of the deque
+        vm->bind(type, "append(self, item) -> None",
+                 [](VM *vm, ArgsView args)
+                 {
+                     PyDeque &self = _CAST(PyDeque &, args[0]);
+                     PyObject *item = args[1];
+                     self.insertObj(false, true, -1, item);
+                     return vm->None;
+                 });
+        // append at the beginning of the deque
+        vm->bind(type, "appendleft(self, item) -> None",
+                 [](VM *vm, ArgsView args)
+                 {
+                     PyDeque &self = _CAST(PyDeque &, args[0]);
+                     PyObject *item = args[1];
+                     self.insertObj(true, false, -1, item);
+                     return vm->None;
+                 });
+        // pop from the end of the deque
+        vm->bind(type, "pop(self) -> PyObject",
+                 [](VM *vm, ArgsView args)
+                 {
+                     PyDeque &self = _CAST(PyDeque &, args[0]);
+                     if (self.dequeItems.empty())
+                     {
+                         vm->IndexError("pop from an empty deque");
+                         return vm->None;
+                     }
+                     return self.popObj(false, true, nullptr, vm);
+                 });
+        // pop from the beginning of the deque
+        vm->bind(type, "popleft(self) -> PyObject",
+                 [](VM *vm, ArgsView args)
+                 {
+                     PyDeque &self = _CAST(PyDeque &, args[0]);
+                     if (self.dequeItems.empty())
+                     {
+                         vm->IndexError("pop from an empty deque");
+                         return vm->None;
+                     }
+                     return self.popObj(true, false, nullptr, vm);
+                 });
+        // shallow copy of the deque
+        vm->bind(type, "copy(self) -> deque",
+                 [](VM *vm, ArgsView args)
+                 {
+                     auto _lock = vm->heap.gc_scope_lock(); // locking the heap
+                     PyDeque &self = _CAST(PyDeque &, args[0]);
+                     PyObject *newDequeObj = vm->heap.gcnew<PyDeque>(PyDeque::_type(vm), vm, vm->None, vm->None); // create the empty deque
+                     PyDeque &newDeque = _CAST(PyDeque &, newDequeObj);                                           // cast it to PyDeque so we can use its methods
+                     for (auto it = self.dequeItems.begin(); it != self.dequeItems.end(); ++it)
+                         newDeque.insertObj(false, true, -1, *it);
+                     return newDequeObj;
+                 });
+        // NEW: counts the number of occurences of the given object in the deque
+        vm->bind(type, "count(self, obj) -> int",
+                 [](VM *vm, ArgsView args)
+                 {
+                     PyDeque &self = _CAST(PyDeque &, args[0]);
+                     PyObject *obj = args[1];
+                     int cnt = 0, sz = self.dequeItems.size();
+                     for (auto it = self.dequeItems.begin(); it != self.dequeItems.end(); ++it)
+                     {
+                         if (vm->py_equals((*it), obj))
+                             cnt++;
+                         if (sz != self.dequeItems.size())// mutating the deque during iteration is not allowed
+                             vm->RuntimeError("deque mutated during iteration"); 
+                     }
+                     return VAR(cnt);
+                 });
+        // NEW: extends the deque from the left
+        vm->bind(type, "extendleft(self, iterable) -> None",
+                 [](VM *vm, ArgsView args)
+                 {
+                     auto _lock = vm->heap.gc_scope_lock();
+                     PyDeque &self = _CAST(PyDeque &, args[0]);
+                     PyObject *it = vm->py_iter(args[1]); // strong ref
+                     PyObject *obj = vm->py_next(it);
+                     while (obj != vm->StopIteration)
+                     {
+                         self.insertObj(true, false, -1, obj);
+                         obj = vm->py_next(it);
+                     }
+                     return vm->None;
+                 });
+        // NEW: returns the index of the given object in the deque
+        vm->bind(type, "index(self, obj, start=None, stop=None) -> int",
+                 [](VM *vm, ArgsView args)
+                 {
+                     // Return the position of x in the deque (at or after index start and before index stop). Returns the first match or raises ValueError if not found.
+                     PyDeque &self = _CAST(PyDeque &, args[0]);
+                     PyObject *obj = args[1];
+                     int start = 0, stop = self.dequeItems.size(); // default values
+                     if (!vm->py_equals(args[2], vm->None))
+                         start = CAST(int, args[2]);
+                     if (!vm->py_equals(args[3], vm->None))
+                         stop = CAST(int, args[3]);
+                     int index = self.findIndex(vm, obj, start, stop);
+                     if (index != -1)
+                         return VAR(index);
+                     else
+                         vm->ValueError(_CAST(Str &, vm->py_repr(obj)) + " is not in deque");
+                     return vm->None;
+                 });
+        // NEW: returns the index of the given object in the deque
+        vm->bind(type, "__contains__(self, obj) -> bool",
+                 [](VM *vm, ArgsView args)
+                 {
+                     // Return the position of x in the deque (at or after index start and before index stop). Returns the first match or raises ValueError if not found.
+                     PyDeque &self = _CAST(PyDeque &, args[0]);
+                     PyObject *obj = args[1];
+                     int start = 0, stop = self.dequeItems.size(); // default values
+                     int index = self.findIndex(vm, obj, start, stop);
+                     if (index != -1)
+                         return VAR(true);
+                     return VAR(false);
+                 });
+        // NEW: inserts the given object at the given index
+        vm->bind(type, "insert(self, index, obj) -> None",
+                 [](VM *vm, ArgsView args)
+                 {
+                     PyDeque &self = _CAST(PyDeque &, args[0]);
+                     int index = CAST(int, args[1]);
+                     PyObject *obj = args[2];
+                     if (self.bounded && self.dequeItems.size() == self.maxlen)
+                         vm->IndexError("deque already at its maximum size");
+                     else
+                         self.insertObj(false, false, index, obj); // this index shouldn't be fixed using vm->normalized_index, pass as is
+                     return vm->None;
+                 });
+        // NEW: removes the first occurence of the given object from the deque
+        vm->bind(type, "remove(self, obj) -> None",
+                 [](VM *vm, ArgsView args)
+                 {
+                     PyDeque &self = _CAST(PyDeque &, args[0]);
+                     PyObject *obj = args[1];
+                     PyObject *removed = self.popObj(false, false, obj, vm);
+                     if (removed == nullptr)
+                         vm->ValueError(_CAST(Str &, vm->py_repr(obj)) + " is not in list");
+                     return vm->None;
+                 });
+        // NEW: reverses the deque
+        vm->bind(type, "reverse(self) -> None",
+                 [](VM *vm, ArgsView args)
+                 {
+                     PyDeque &self = _CAST(PyDeque &, args[0]);
+                     if (self.dequeItems.empty() || self.dequeItems.size() == 1)
+                         return vm->None; // handle trivial cases
+                     int sz = self.dequeItems.size();
+                     for (int i = 0; i < sz / 2; i++)
+                     {
+                         PyObject *tmp = self.dequeItems[i];
+                         self.dequeItems[i] = self.dequeItems[sz - i - 1]; // swapping
+                         self.dequeItems[sz - i - 1] = tmp;
+                     }
+                     return vm->None;
+                 });
+        // NEW: rotates the deque by n steps
+        vm->bind(type, "rotate(self, n=1) -> None",
+                 [](VM *vm, ArgsView args)
+                 {
+                     PyDeque &self = _CAST(PyDeque &, args[0]);
+                     int n = CAST(int, args[1]);
+
+                     if (n != 0 && !self.dequeItems.empty()) // trivial case
+                     {
+                         PyObject *tmp; // holds the object to be rotated
+                         int direction = n > 0 ? 1 : -1;
+                         n = abs(n);
+                         n = n % self.dequeItems.size(); // make sure n is in range
+                         while (n--)
+                         {
+                             if (direction == 1)
+                             {
+                                 tmp = self.dequeItems.back();
+                                 self.dequeItems.pop_back();
+                                 self.dequeItems.push_front(tmp);
+                             }
+                             else
+                             {
+                                 tmp = self.dequeItems.front();
+                                 self.dequeItems.pop_front();
+                                 self.dequeItems.push_back(tmp);
+                             }
+                         }
+                     }
+                     return vm->None;
+                 });
+        // NEW: getter and setter of property `maxlen`
+        vm->bind_property(
+            type, "maxlen: int",
+            [](VM *vm, ArgsView args)
+            {
+                PyDeque &self = _CAST(PyDeque &, args[0]);
+                if (self.bounded)
+                    return VAR(self.maxlen);
+                return vm->None;
+            },
+            [](VM *vm, ArgsView args)
+            {
+                vm->AttributeError("attribute 'maxlen' of 'collections.deque' objects is not writable");
+                return vm->None;
+            });
+        // NEW: support pickle
+        vm->bind(type, "__getnewargs__(self) -> tuple[list, int]",
+                 [](VM *vm, ArgsView args)
+                 {
+                     PyDeque &self = _CAST(PyDeque &, args[0]);
+                     Tuple ret(2);
+                     List list;
+                     for (PyObject *obj : self.dequeItems)
+                     {
+                         list.push_back(obj);
+                     }
+                     ret[0] = VAR(std::move(list));
+                     if (self.bounded)
+                         ret[1] = VAR(self.maxlen);
+                     else
+                         ret[1] = vm->None;
+                     return VAR(ret);
+                 });
+    }
+    /// @brief initializes a new PyDeque object, actual initialization is done in __init__
+    PyDeque::PyDeque(VM *vm, PyObject *iterable, PyObject *maxlen)
+    {
+
+        if (!vm->py_equals(maxlen, vm->None)) // fix the maxlen first
+        {
+            int tmp = CAST(int, maxlen);
+            if (tmp < 0)
+                vm->ValueError("maxlen must be non-negative");
+            else
+            {
+                this->maxlen = tmp;
+                this->bounded = true;
+            }
+        }
+        else
+        {
+            this->bounded = false;
+            this->maxlen = -1;
+        }
+        if (!vm->py_equals(iterable, vm->None))
+        {
+            this->dequeItems.clear();              // clear the deque
+            auto _lock = vm->heap.gc_scope_lock(); // locking the heap
+            PyObject *it = vm->py_iter(iterable);  // strong ref
+            PyObject *obj = vm->py_next(it);
+            while (obj != vm->StopIteration)
+            {
+                this->insertObj(false, true, -1, obj);
+                obj = vm->py_next(it);
+            }
+        }
+    }
+    std::stringstream PyDeque::getRepr(VM *vm, PyObject *thisObj)
+    {
+        std::stringstream ss;
+        ss << "deque([";
+        for (auto it = this->dequeItems.begin(); it != this->dequeItems.end(); ++it)
+        {
+            if (*it == thisObj)
+                ss << "[...]";
+            else
+                ss << CAST(Str &, vm->py_repr(*it));
+            if (it != this->dequeItems.end() - 1)
+                ss << ", ";
+        }
+        this->bounded ? ss << "], maxlen=" << this->maxlen << ")" : ss << "])";
+        return ss;
+    }
+    int PyDeque::findIndex(VM *vm, PyObject *obj, int start, int stop)
+    {
+        // the following code is special purpose normalization for this method, taken from CPython: _collectionsmodule.c file
+        if (start < 0)
+        {
+            start = this->dequeItems.size() + start; // try to fix for negative indices
+            if (start < 0)
+                start = 0;
+        }
+        if (stop < 0)
+        {
+            stop = this->dequeItems.size() + stop; // try to fix for negative indices
+            if (stop < 0)
+                stop = 0;
+        }
+        if (stop > this->dequeItems.size())
+            stop = this->dequeItems.size();
+        if (start > stop)
+            start = stop;                                                                                                           // end of normalization
+        PK_ASSERT(start >= 0 && start <= this->dequeItems.size() && stop >= 0 && stop <= this->dequeItems.size() && start <= stop); // sanity check
+        int loopSize = std::min((int)(this->dequeItems.size()), stop);
+        int sz = this->dequeItems.size();
+        for (int i = start; i < loopSize; i++)
+        {
+            if (vm->py_equals(this->dequeItems[i], obj))
+                return i;
+            if (sz != this->dequeItems.size())// mutating the deque during iteration is not allowed
+                vm->RuntimeError("deque mutated during iteration");
+        }
+        return -1;
+    }
+
+    /// @brief pops or removes an item from the deque
+    /// @param front  if true, pop from the front of the deque
+    /// @param back if true, pop from the back of the deque
+    /// @param item if front and back is not set, remove the first occurence of item from the deque
+    /// @param vm is needed for the py_equals
+    /// @return PyObject* if front or back is set, this is a pop operation and we return a PyObject*, if front and back are not set, this is a remove operation and we return the removed item or nullptr
+    PyObject *PyDeque::popObj(bool front, bool back, PyObject *item, VM *vm)
+    {
+        // error handling
+        if (front && back)
+            throw std::runtime_error("both front and back are set"); // this should never happen
+        if (front || back)
+        {
+            // front or back is set, we don't care about item, this is a pop operation and we return a PyObject*
+            if (this->dequeItems.empty())
+                throw std::runtime_error("pop from an empty deque"); // shouldn't happen
+            PyObject *obj;
+            if (front)
+            {
+                obj = this->dequeItems.front();
+                this->dequeItems.pop_front();
+            }
+            else
+            {
+                obj = this->dequeItems.back();
+                this->dequeItems.pop_back();
+            }
+            return obj;
+        }
+        else
+        {
+            // front and back are not set, we care about item, this is a remove operation and we return the removed item or nullptr
+            int sz = this->dequeItems.size();
+            for (auto it = this->dequeItems.begin(); it != this->dequeItems.end(); ++it)
+            {
+                bool found = vm->py_equals((*it), item);
+                if (sz != this->dequeItems.size()) // mutating the deque during iteration is not allowed
+                    vm->IndexError("deque mutated during iteration");
+                if (found)
+                {
+                    PyObject *obj = *it; // keep a reference to the object for returning
+                    this->dequeItems.erase(it);
+                    return obj;
+                }
+            }
+            return nullptr; // not found
+        }
+    }
+    /// @brief inserts an item into the deque
+    /// @param front if true, insert at the front of the deque
+    /// @param back if true, insert at the back of the deque
+    /// @param index if front and back are not set, insert at the given index
+    /// @param item the item to insert
+    /// @return true if the item was inserted successfully, false if the deque is bounded and is already at its maximum size
+    void PyDeque::insertObj(bool front, bool back, int index, PyObject *item) // assume index is not fixed using the vm->normalized_index
+    {
+        // error handling
+        if (front && back)
+            throw std::runtime_error("both front and back are set"); // this should never happen
+        if (front || back)
+        {
+            // front or back is set, we don't care about index
+            if (this->bounded)
+            {
+                if (this->maxlen == 0)
+                    return; // bounded and maxlen is 0, so we can't append
+                else if (this->dequeItems.size() == this->maxlen)
+                {
+                    if (front)
+                        this->dequeItems.pop_back(); // remove the last item
+                    else if (back)
+                        this->dequeItems.pop_front(); // remove the first item
+                }
+            }
+            if (front)
+                this->dequeItems.emplace_front(item);
+            else if (back)
+                this->dequeItems.emplace_back(item);
+        }
+        else
+        {
+            // front and back are not set, we care about index
+            if (index < 0)
+                index = this->dequeItems.size() + index; // try fixing for negative indices
+            if (index < 0)                               // still negative means insert at the beginning
+                this->dequeItems.push_front(item);
+            else if (index >= this->dequeItems.size()) // still out of range means insert at the end
+                this->dequeItems.push_back(item);
+            else
+                this->dequeItems.insert((this->dequeItems.begin() + index), item); // insert at the given index
+        }
+    }
+    /// @brief marks the deque items for garbage collection
+    void PyDeque::_gc_mark() const
+    {
+        for (PyObject *obj : this->dequeItems)
+            PK_OBJ_MARK(obj);
+    }
+    /// @brief registers the PyDeque class
+    /// @param vm is needed for the new_module and register_class
+    void add_module_collections(VM *vm)
+    {
+        PyObject *mod = vm->new_module("collections");
+        PyDeque::register_class(vm, mod);
+        PyDequeIter::register_class(vm, vm->builtins);
+        CodeObject_ code = vm->compile(kPythonLibs["collections"], "collections.py", EXEC_MODE);
+        vm->_exec(code, mod);
+    }
+} // namespace pkpypkpy
diff --git a/src/pocketpy.cpp b/src/pocketpy.cpp
index 5fc50fd2..de5d6ecd 100644
--- a/src/pocketpy.cpp
+++ b/src/pocketpy.cpp
@@ -1649,7 +1649,7 @@ void VM::post_init(){
     add_module_base64(this);
     add_module_timeit(this);
 
-    for(const char* name: {"this", "functools", "collections", "heapq", "bisect", "pickle", "_long", "colorsys", "typing", "datetime"}){
+    for(const char* name: {"this", "functools", "heapq", "bisect", "pickle", "_long", "colorsys", "typing", "datetime"}){
         _lazy_modules[name] = kPythonLibs[name];
     }
 
@@ -1672,6 +1672,7 @@ void VM::post_init(){
 
     add_module_linalg(this);
     add_module_easing(this);
+    add_module_collections(this);
 
 #ifdef PK_USE_BOX2D
     add_module_box2d(this);
diff --git a/tests/70_collections.py b/tests/70_collections.py
index 477b16d3..7d967d01 100644
--- a/tests/70_collections.py
+++ b/tests/70_collections.py
@@ -1,16 +1,831 @@
 from collections import Counter, deque
+import random
+import pickle
+import gc
+import builtins
 
 q = deque()
 q.append(1)
 q.append(2)
 q.appendleft(3)
 q.append(4)
-
 assert len(q) == 4
-
 assert q == deque([3, 1, 2, 4])
 assert q.popleft() == 3
 assert q.pop() == 4
-
 assert len(q) == 2
-assert q == deque([1, 2])
\ No newline at end of file
+assert q == deque([1, 2])
+
+# ADDING TESTS FROM CPYTHON's test_deque.py file
+
+############ TEST basics###############
+
+
+def assertEqual(a, b):
+    assert a == b
+def assertNotEqual(a, b):
+    assert a != b
+def printFailed(function_name, *args, **kwargs):
+    print("X Failed Tests for {} for args: {} {}".format(str(function_name), str(args), str(kwargs)))
+
+
+BIG = 100000
+
+
+def fail():
+    raise SyntaxError
+    yield 1
+
+
+d = deque(range(-5125, -5000))
+# d.__init__(range(200)) # not supported
+d = deque(range(200))
+for i in range(200, 400):
+    d.append(i)
+for i in reversed(range(-200, 0)):
+    d.appendleft(i)
+
+assertEqual(list(d), list(range(-200, 400)))
+assertEqual(len(d), 600)
+
+left = [d.popleft() for i in range(250)]
+assertEqual(left, list(range(-200, 50)))
+assertEqual(list(d), list(range(50, 400)))
+
+right = [d.pop() for i in range(250)]
+right.reverse()
+assertEqual(right, list(range(150, 400)))
+assertEqual(list(d), list(range(50, 150)))
+
+####### TEST maxlen###############
+try:
+    dq = deque()
+    dq.maxlen = -1
+    printFailed("deque.maxlen", -1)
+    exit(1)
+except AttributeError:
+    pass
+
+try:
+    dq = deque()
+    dq.maxlen = -2
+    printFailed("deque.maxlen", -2)
+    exit(1)
+except AttributeError:
+    pass
+
+it = iter(range(10))
+d = deque(it, maxlen=3)
+assertEqual(list(it), [])
+assertEqual(repr(d), 'deque([7, 8, 9], maxlen=3)')
+assertEqual(list(d), [7, 8, 9])
+assertEqual(d, deque(range(10), 3))
+d.append(10)
+assertEqual(list(d), [8, 9, 10])
+d.appendleft(7)
+assertEqual(list(d), [7, 8, 9])
+d.extend([10, 11])
+assertEqual(list(d), [9, 10, 11])
+d.extendleft([8, 7])
+assertEqual(list(d), [7, 8, 9])
+d = deque(range(200), maxlen=10)
+d.append(d)
+assertEqual(repr(d)[-30:], ', 198, 199, [...]], maxlen=10)')
+d = deque(range(10), maxlen=None)
+assertEqual(repr(d), 'deque([0, 1, 2, 3, 4, 5, 6, 7, 8, 9])')
+
+####### TEST maxlen = 0###############
+it = iter(range(100))
+deque(it, maxlen=0)
+assertEqual(list(it), [])
+
+it = iter(range(100))
+d = deque(maxlen=0)
+d.extend(it)
+assertEqual(list(it), [])
+
+it = iter(range(100))
+d = deque(maxlen=0)
+d.extendleft(it)
+assertEqual(list(it), [])
+
+
+####### TEST maxlen attribute #############
+
+assertEqual(deque().maxlen, None)
+assertEqual(deque('abc').maxlen, None)
+assertEqual(deque('abc', maxlen=4).maxlen, 4)
+assertEqual(deque('abc', maxlen=2).maxlen, 2)
+assertEqual(deque('abc', maxlen=0).maxlen, 0)
+try:
+    d = deque('abc')
+    d.maxlen = 10
+    printFailed("deque.maxlen", 10)
+    exit(1)
+except AttributeError:
+    pass
+
+######### TEST count()#################
+for s in ('', 'abracadabra', 'simsalabim'*500+'abc'):
+    s = list(s)
+    d = deque(s)
+    for letter in 'abcdefghijklmnopqrstuvwxyz':
+        assertEqual(s.count(letter), d.count(letter))
+try:
+    d.count()
+    printFailed("deque.count")
+    exit(1)
+except TypeError:
+    pass
+
+try:
+    d.count(1, 2)
+    printFailed("deque.count", 1, 2)
+    exit(1)
+except TypeError:
+    pass
+
+
+class BadCompare:
+    def __eq__(self, other):
+        raise ArithmeticError
+
+
+d = deque([1, 2, BadCompare(), 3])
+
+try:
+    d.count(2)
+    printFailed("deque.count", 2)
+    exit(1)
+except ArithmeticError:
+    pass
+
+d = deque([1, 2, 3])
+try:
+    d.count(BadCompare())
+    printFailed("deque.count", "BadCompare()")
+    exit(1)
+except ArithmeticError:
+    pass
+
+
+class MutatingCompare:
+    def __eq__(self, other):
+        d.pop()
+        return True
+
+
+m = MutatingCompare()
+d = deque([1, 2, 3, m, 4, 5])
+m.d = d
+
+try:
+    d.count(3)
+    printFailed("deque.count", "MutatingCompare()")
+    exit(1)
+except RuntimeError:
+    pass
+
+d = deque([None]*16)
+for i in range(len(d)):
+    d.rotate(-1)
+d.rotate(1)
+assertEqual(d.count(1), 0)
+assertEqual(d.count(None), 16)
+
+#### TEST comparisons == #####
+
+d = deque('xabc')
+d.popleft()
+for e in [d, deque('abc'), deque('ab'), deque(), list(d)]:
+    assertEqual(d == e, type(d) == type(e) and list(d) == list(e))
+    assertEqual(d != e, not (type(d) == type(e) and list(d) == list(e)))
+
+args = map(deque, ('', 'a', 'b', 'ab', 'ba', 'abc', 'xba', 'xabc', 'cba'))
+for x in args:
+    for y in args:
+        assertEqual(x == y, list(x) == list(y))
+        assertEqual(x != y, list(x) != list(y))
+        # assertEqual(x <  y, list(x) <  list(y))   # not currently supported
+        # assertEqual(x <= y, list(x) <= list(y))   # not currently supported
+        # assertEqual(x >  y, list(x) >  list(y))   # not currently supported
+        # assertEqual(x >= y, list(x) >= list(y))   # not currently supported
+
+
+############### TEST contains()#################
+
+n = 200
+
+d = deque(range(n))
+for i in range(n):
+    assertEqual(i in d, True)
+assertEqual((n+1) not in d, True)
+
+
+class MutateCmp:
+    def __init__(self, deque, result):
+        self.deque = deque
+        self.result = result
+
+    def __eq__(self, other):
+        self.deque.clear()
+        return self.result
+
+
+# # Test detection of mutation during iteration
+d = deque(range(n))
+d[n//2] = MutateCmp(d, False)
+try:
+    n in d
+    printFailed("deque.__contains__", n)
+    exit(1)
+except RuntimeError:
+    pass
+
+
+class BadCmp:
+    def __eq__(self, other):
+        raise RuntimeError
+
+
+# # Test detection of comparison exceptions
+d = deque(range(n))
+d[n//2] = BadCmp()
+try:
+    n in d
+    printFailed("deque.__contains__", n)
+    exit(1)
+except RuntimeError:
+    pass
+
+
+##### test_contains_count_stop_crashes#####
+
+class A:
+    def __eq__(self, other):
+        d.clear()
+        return NotImplemented
+
+
+d = deque([A(), A()])
+
+try:
+    _ = 3 in d
+    printFailed("deque.__contains__", 3)
+    exit(1)
+except RuntimeError:
+    pass
+
+d = deque([A(), A()])
+try:
+    _ = d.count(3)
+    printFailed("deque.count", 3)
+    exit(1)
+except RuntimeError:
+    pass
+
+
+######## TEST extend()################
+
+
+d = deque('a')
+try:
+    d.extend(1)
+    printFailed("deque.extend", 1)
+    exit(1)
+except TypeError:
+    pass
+d.extend('bcd')
+assertEqual(list(d), list('abcd'))
+d.extend(d)
+assertEqual(list(d), list('abcdabcd'))
+
+###### TEST extend_left() ################
+
+d = deque('a')
+try:
+    d.extendleft(1)
+    printFailed("deque.extendleft", 1)
+    exit(1)
+except TypeError:
+    pass
+d.extendleft('bcd')
+assertEqual(list(d), list(reversed('abcd')))
+d.extendleft(d)
+assertEqual(list(d), list('abcddcba'))
+d = deque()
+d.extendleft(range(1000))
+assertEqual(list(d), list(reversed(range(1000))))
+try:
+    d.extendleft(fail())
+    printFailed("deque.extendleft", fail())
+    exit(1)
+except SyntaxError:
+    pass
+
+##### TEST get_item ################
+
+n = 200
+d = deque(range(n))
+l = list(range(n))
+for i in range(n):
+    d.popleft()
+    l.pop(0)
+    if random.random() < 0.5:
+        d.append(i)
+        l.append(i)
+    for j in range(1-len(l), len(l)):
+        assert d[j] == l[j]
+
+d = deque('superman')
+assertEqual(d[0], 's')
+assertEqual(d[-1], 'n')
+d = deque()
+try:
+    d.__getitem__(0)
+    printFailed("deque.__getitem__", 0)
+    exit(1)
+except IndexError:
+    pass
+try:
+    d.__getitem__(-1)
+    printFailed("deque.__getitem__", -1)
+    exit(1)
+except IndexError:
+    pass
+
+
+######### TEST index()###############
+for n in 1, 2, 30, 40, 200:
+
+    d = deque(range(n))
+    for i in range(n):
+        assertEqual(d.index(i), i)
+
+    try:
+        d.index(n+1)
+        printFailed("deque.index", n+1)
+        exit(1)
+    except ValueError:
+        pass
+
+    # Test detection of mutation during iteration
+    d = deque(range(n))
+    d[n//2] = MutateCmp(d, False)
+
+    try:
+        d.index(n)
+        printFailed("deque.index", n)
+        exit(1)
+    except RuntimeError:
+        pass
+
+    # Test detection of comparison exceptions
+    d = deque(range(n))
+    d[n//2] = BadCmp()
+
+    try:
+        d.index(n)
+        printFailed("deque.index", n)
+        exit(1)
+    except RuntimeError:
+        pass
+
+
+# Test start and stop arguments behavior matches list.index()
+# COMMENT: Current List behavior doesn't support start and stop arguments, so this test is not supported
+# elements = 'ABCDEFGHI'
+# nonelement = 'Z'
+# d = deque(elements * 2)
+# s = list(elements * 2)
+# for start in range(-5 - len(s)*2, 5 + len(s) * 2):
+#     for stop in range(-5 - len(s)*2, 5 + len(s) * 2):
+#         for element in elements + 'Z':
+#             try:
+#                 print(element, start, stop)
+#                 target = s.index(element, start, stop)
+#             except ValueError:
+#                 try:
+#                     d.index(element, start, stop)
+#                     print("X Failed Tests!")
+#                     exit(1)
+#                 except ValueError:
+#                     continue
+#                 # with assertRaises(ValueError):
+#                 #     d.index(element, start, stop)
+#             assertEqual(d.index(element, start, stop), target)
+
+
+# Test large start argument
+d = deque(range(0, 10000, 10))
+for step in range(100):
+    i = d.index(8500, 700)
+    assertEqual(d[i], 8500)
+    # Repeat test with a different internal offset
+    d.rotate()
+
+########### test_index_bug_24913#############
+d = deque('A' * 3)
+try:
+    d.index('A', 1, 0)
+    printFailed("deque.index", 'A', 1, 0)
+    exit(1)
+except ValueError:
+    pass
+
+########### test_insert#############
+   # Test to make sure insert behaves like lists
+elements = 'ABCDEFGHI'
+for i in range(-5 - len(elements)*2, 5 + len(elements) * 2):
+    d = deque('ABCDEFGHI')
+    s = list('ABCDEFGHI')
+    d.insert(i, 'Z')
+    s.insert(i, 'Z')
+    assertEqual(list(d), s)
+
+
+########### test_insert_bug_26194#############
+data = 'ABC'
+d = deque(data, maxlen=len(data))
+try:
+    d.insert(0, 'Z')
+    printFailed("deque.insert", 0, 'Z')
+    exit(1)
+except IndexError:
+    pass
+
+elements = 'ABCDEFGHI'
+for i in range(-len(elements), len(elements)):
+    d = deque(elements, maxlen=len(elements)+1)
+    d.insert(i, 'Z')
+    if i >= 0:
+        assertEqual(d[i], 'Z')
+    else:
+        assertEqual(d[i-1], 'Z')
+
+
+######### test set_item #############
+n = 200
+d = deque(range(n))
+for i in range(n):
+    d[i] = 10 * i
+assertEqual(list(d), [10*i for i in range(n)])
+l = list(d)
+for i in range(1-n, 0, -1):
+    d[i] = 7*i
+    l[i] = 7*i
+assertEqual(list(d), l)
+
+
+########## test del_item #############
+n = 500         # O(n**2) test, don't make this too big
+d = deque(range(n))
+try:
+    d.__delitem__(-n-1)
+    printFailed("deque.__delitem__", -n-1)
+    exit(1)
+except IndexError:
+    pass
+
+try:
+    d.__delitem__(n)
+    printFailed("deque.__delitem__", n)
+    exit(1)
+except IndexError:
+    pass
+for i in range(n):
+    assertEqual(len(d), n-i)
+    j = random.randint(0, len(d)-1)
+    val = d[j]
+    assertEqual(val in d, True)
+    del d[j]
+    assertEqual(val in d, False)
+assertEqual(len(d), 0)
+
+
+######### test reverse()###############
+
+n = 500         # O(n**2) test, don't make this too big
+data = [random.random() for i in range(n)]
+for i in range(n):
+    d = deque(data[:i])
+    r = d.reverse()
+    assertEqual(list(d), list(reversed(data[:i])))
+    assertEqual(r, None)
+    d.reverse()
+    assertEqual(list(d), data[:i])
+try:
+    d.reverse(1)
+    printFailed("deque.reverse", 1)
+    exit(1)
+except TypeError:
+    pass
+
+############ test rotate#############
+s = tuple('abcde')
+n = len(s)
+
+d = deque(s)
+d.rotate(1)             # verify rot(1)
+assertEqual(''.join(d), 'eabcd')
+
+d = deque(s)
+d.rotate(-1)            # verify rot(-1)
+assertEqual(''.join(d), 'bcdea')
+d.rotate()              # check default to 1
+assertEqual(tuple(d), s)
+
+for i in range(n*3):
+    d = deque(s)
+    e = deque(d)
+    d.rotate(i)         # check vs. rot(1) n times
+    for j in range(i):
+        e.rotate(1)
+    assertEqual(tuple(d), tuple(e))
+    d.rotate(-i)        # check that it works in reverse
+    assertEqual(tuple(d), s)
+    e.rotate(n-i)       # check that it wraps forward
+    assertEqual(tuple(e), s)
+
+for i in range(n*3):
+    d = deque(s)
+    e = deque(d)
+    d.rotate(-i)
+    for j in range(i):
+        e.rotate(-1)    # check vs. rot(-1) n times
+    assertEqual(tuple(d), tuple(e))
+    d.rotate(i)         # check that it works in reverse
+    assertEqual(tuple(d), s)
+    e.rotate(i-n)       # check that it wraps backaround
+    assertEqual(tuple(e), s)
+
+d = deque(s)
+e = deque(s)
+e.rotate(BIG+17)        # verify on long series of rotates
+dr = d.rotate
+for i in range(BIG+17):
+    dr()
+assertEqual(tuple(d), tuple(e))
+try:
+    d.rotate(1, 2)
+    printFailed("deque.rotate", 1, 2)
+    exit(1)
+except TypeError:
+    pass
+
+try:
+    d.rotate(1, 10)
+    printFailed("deque.rotate", 1, 10)
+    exit(1)
+except TypeError:
+    pass
+d = deque()
+d.rotate()              # rotate an empty deque
+assertEqual(d, deque())
+
+
+########## test len#############
+
+d = deque('ab')
+assertEqual(len(d), 2)
+d.popleft()
+assertEqual(len(d), 1)
+d.pop()
+assertEqual(len(d), 0)
+try:
+    d.pop()
+    printFailed("deque.pop")
+    exit(1)
+except IndexError:
+    pass
+assertEqual(len(d), 0)
+d.append('c')
+assertEqual(len(d), 1)
+d.appendleft('d')
+assertEqual(len(d), 2)
+d.clear()
+assertEqual(len(d), 0)
+
+
+############## test underflow#############
+d = deque()
+try:
+    d.pop()
+    printFailed("deque.pop")
+    exit(1)
+except IndexError:
+    pass
+try:
+    d.popleft()
+    printFailed("deque.popleft")
+    exit(1)
+except IndexError:
+    pass
+
+############## test clear#############
+d = deque(range(100))
+assertEqual(len(d), 100)
+d.clear()
+assertEqual(len(d), 0)
+assertEqual(list(d), [])
+d.clear()               # clear an empty deque
+assertEqual(list(d), [])
+
+
+############# test remove#############
+d = deque('abcdefghcij')
+d.remove('c')
+assertEqual(d, deque('abdefghcij'))
+d.remove('c')
+assertEqual(d, deque('abdefghij'))
+try:
+    d.remove('c')
+    printFailed("deque.remove", "c")
+    exit(1)
+except ValueError:
+    pass
+assertEqual(d, deque('abdefghij'))
+
+# Handle comparison errors
+d = deque(['a', 'b', BadCmp(), 'c'])
+e = deque(d)
+
+try:
+    d.remove('c')
+    printFailed("deque.remove", "c")
+    exit(1)
+except RuntimeError:
+    pass
+for x, y in zip(d, e):
+    # verify that original order and values are retained.
+    assertEqual(x is y, True)
+
+# Handle evil mutator
+for match in (True, False):
+    d = deque(['ab'])
+    d.extend([MutateCmp(d, match), 'c'])
+    try:
+        d.remove('c')
+        printFailed("deque.remove", "c")
+        exit(1)
+    except IndexError:
+        pass
+    assertEqual(d, deque())
+
+
+########### test repr#############
+d = deque(range(200))
+e = eval(repr(d))
+assertEqual(list(d), list(e))
+d.append(d)
+assertEqual(repr(d)[-20:], '7, 198, 199, [...]])')
+
+
+######### test init #############
+
+try:
+    deque('abc', 2, 3)
+    printFailed("deque", 'abc', 2, 3)
+    exit(1)
+except TypeError:
+    pass
+try:
+    deque(1)
+    printFailed("deque", 1)
+    exit(1)
+except TypeError:
+    pass
+
+
+######### test hash #############
+try:
+    hash(deque('abcd'))
+except TypeError:
+    pass
+
+
+###### test long steady state queue pop left ########
+for size in (0, 1, 2, 100, 1000):
+    d = deque(range(size))
+    append, pop = d.append, d.popleft
+    for i in range(size, BIG):
+        append(i)
+        x = pop()
+        if x != i - size:
+            assertEqual(x, i-size)
+    assertEqual(list(d), list(range(BIG-size, BIG)))
+
+
+######## test long steady state queue pop right ########
+for size in (0, 1, 2, 100, 1000):
+    d = deque(reversed(range(size)))
+    append, pop = d.appendleft, d.pop
+    for i in range(size, BIG):
+        append(i)
+        x = pop()
+        if x != i - size:
+            assertEqual(x, i-size)
+    assertEqual(list(reversed(list(d))),
+                list(range(BIG-size, BIG)))
+
+###### test big queue popleft ########
+d = deque()
+append, pop = d.append, d.popleft
+for i in range(BIG):
+    append(i)
+for i in range(BIG):
+    x = pop()
+    if x != i:
+        assertEqual(x, i)
+
+###### test big queue pop right ########
+d = deque()
+append, pop = d.appendleft, d.pop
+for i in range(BIG):
+    append(i)
+for i in range(BIG):
+    x = pop()
+    if x != i:
+        assertEqual(x, i)
+
+
+####### test big stack right########
+d = deque()
+append, pop = d.append, d.pop
+for i in range(BIG):
+    append(i)
+for i in reversed(range(BIG)):
+    x = pop()
+    if x != i:
+        assertEqual(x, i)
+assertEqual(len(d), 0)
+
+
+##### test big stack left ########
+d = deque()
+append, pop = d.appendleft, d.popleft
+for i in range(BIG):
+    append(i)
+for i in reversed(range(BIG)):
+    x = pop()
+    if x != i:
+        assertEqual(x, i)
+assertEqual(len(d), 0)
+
+
+##### test roundtrip iter init ########
+d = deque(range(200))
+e = deque(d)
+assertNotEqual(id(d), id(e))
+assertEqual(list(d), list(e))
+
+
+########## test pickle #############
+
+for d in deque(range(200)), deque(range(200), 100):
+    for i in range(5 + 1):
+        s = pickle.dumps(d)
+        e = pickle.loads(s)
+        assertNotEqual(id(e), id(d))
+        assertEqual(list(e), list(d))
+        assertEqual(e.maxlen, d.maxlen)
+
+######## test pickle recursive ########
+# the following doesn't work because the pickle module doesn't
+# for d in deque('abc'), deque('abc', 3):
+#     d.append(d)
+#     for i in range(5 + 1):
+#         e = pickle.loads(pickle.dumps(d))
+#         assertNotEqual(id(e), id(d))
+#         assertEqual(id(e[-1]), id(e))
+#         assertEqual(e.maxlen, d.maxlen)
+
+
+### test copy ########
+
+mut = [10]
+d = deque([mut])
+e = d.copy()
+assertEqual(list(d), list(e))
+mut[0] = 11
+assertNotEqual(id(d), id(e))
+assertEqual(list(d), list(e))
+
+### test reversed#$####
+
+for s in ('abcd', range(2000)):
+    assertEqual(list(reversed(deque(s))), list(reversed(s)))
+
+
+# probably not supported
+# klass = type(reversed(deque()))
+# for s in ('abcd', range(2000)):
+#     assertEqual(list(klass(deque(s))), list(reversed(s)))
+
+d = deque()
+for i in range(100):
+    d.append(1)
+    gc.collect()
+
+
+print('✓', "ALL TEST PASSED!!")