diff --git a/python/collections.py b/python/collections.py
index 3698fff6..05fdd03d 100644
--- a/python/collections.py
+++ b/python/collections.py
@@ -20,6 +20,9 @@ class defaultdict:
     def __setitem__(self, key, value):
         self._a[key] = value
 
+    def __delitem__(self, key):
+        del self._a[key]
+
     def __repr__(self) -> str:
         return f"defaultdict({self.default_factory}, {self._a})"
     
@@ -50,3 +53,17 @@ class defaultdict:
 
     def pop(self, *args):
         return self._a.pop(*args)
+
+    def clear(self):
+        self._a.clear()
+
+    def copy(self):
+        new_dd = defaultdict(self.default_factory)
+        new_dd._a = self._a.copy()
+        return new_dd
+    
+    def get(self, key, default):
+        return self._a.get(key, default)
+    
+    def update(self, other):
+        self._a.update(other)
diff --git a/tests/70_collections.py b/tests/70_collections.py
index e9fe02b7..17d39314 100644
--- a/tests/70_collections.py
+++ b/tests/70_collections.py
@@ -1,9 +1,17 @@
-from collections import Counter, deque
+from collections import Counter, deque, defaultdict
 import random
 import pickle
 import gc
 import builtins
 
+dd_dict_keys = sorted(defaultdict.__dict__.keys())
+d_dict_keys = sorted(dict.__dict__.keys())
+d_dict_keys.remove('__new__')
+if dd_dict_keys != d_dict_keys:
+    print("dd_dict_keys:", dd_dict_keys)
+    print("d_dict_keys:", d_dict_keys)
+    raise Exception("dd_dict_keys != d_dict_keys")
+
 q = deque()
 q.append(1)
 q.append(2)