diff --git a/README.md b/README.md
index d7fc2047..b06fab87 100644
--- a/README.md
+++ b/README.md
@@ -92,41 +92,63 @@ python scripts/run_tests.py
 
 ### Example
 
-```cpp
+```c
 #include "pocketpy.h"
+#include <stdio.h>
 
-using namespace pkpy;
+static bool int_add(int argc, py_Ref argv) {
+    PY_CHECK_ARGC(2);
+    PY_CHECK_ARG_TYPE(0, tp_int);
+    PY_CHECK_ARG_TYPE(1, tp_int);
+    py_i64 a = py_toint(py_arg(0));
+    py_i64 b = py_toint(py_arg(1));
+    py_newint(py_retval(), a + b);
+    return true;
+}
 
-int main(){
-    // Create a virtual machine
-    VM* vm = new VM();
+int main() {
+    // Initialize pocketpy
+    py_initialize();
 
     // Hello world!
-    vm->exec("print('Hello world!')");
+    bool ok = py_exec("print('Hello world!')", "<string>", EXEC_MODE, NULL);
+    if(!ok) goto __ERROR;
 
-    // Create a list
-    vm->exec("a = [1, 2, 3]");
+    // Create a list: [1, 2, 3]
+    py_Ref r0 = py_getreg(0);
+    py_newlistn(r0, 3);
+    py_newint(py_list_getitem(r0, 0), 1);
+    py_newint(py_list_getitem(r0, 1), 2);
+    py_newint(py_list_getitem(r0, 2), 3);
 
     // Eval the sum of the list
-    PyVar result = vm->eval("sum(a)");
-    std::cout << "Sum of the list: "<< py_cast<int>(vm, result) << std::endl;   // 6
+    py_Ref f_sum = py_getbuiltin(py_name("sum"));
+    py_push(f_sum);
+    py_pushnil();
+    py_push(r0);
+    ok = py_vectorcall(1, 0);
+    if(!ok) goto __ERROR;
 
-    // Bindings
-    vm->bind(vm->_main, "add(a: int, b: int)",
-      [](VM* vm, ArgsView args){
-        int a = py_cast<int>(vm, args[0]);
-        int b = py_cast<int>(vm, args[1]);
-        return py_var(vm, a + b);
-      });
+    printf("Sum of the list: %d\n", (int)py_toint(py_retval()));  // 6
 
-    // Call the function
-    PyVar f_add = vm->_main->attr("add");
-    result = vm->call(f_add, py_var(vm, 3), py_var(vm, 7));
-    std::cout << "Sum of 2 variables: "<< py_cast<int>(vm, result) << std::endl;   // 10
+    // Bind native `int_add` as a global variable
+    py_newnativefunc(r0, int_add);
+    py_setglobal(py_name("add"), r0);
 
-    // Dispose the virtual machine
-    delete vm;
+    // Call `add` in python
+    ok = py_exec("add(3, 7)", "<string>", EVAL_MODE, NULL);
+    if(!ok) goto __ERROR;
+
+    py_i64 res = py_toint(py_retval());
+    printf("Sum of 2 variables: %d\n", (int)res);  // 10
+
+    py_finalize();
     return 0;
+
+__ERROR:
+    py_printexc();
+    py_finalize();
+    return 1;
 }
 ```
 
diff --git a/include/pocketpy/pocketpy.h b/include/pocketpy/pocketpy.h
index 98f67823..00024863 100644
--- a/include/pocketpy/pocketpy.h
+++ b/include/pocketpy/pocketpy.h
@@ -3,6 +3,7 @@
 #include <stdint.h>
 #include <stdbool.h>
 #include <stdarg.h>
+#include <stddef.h>
 
 #include "pocketpy/common/config.h"
 #include "pocketpy/common/export.h"
diff --git a/src/interpreter/ceval.c b/src/interpreter/ceval.c
index 0934ddbf..db956de0 100644
--- a/src/interpreter/ceval.c
+++ b/src/interpreter/ceval.c
@@ -921,7 +921,6 @@ FrameResult VM__run_top_frame(VM* self) {
                     // call on_end_subclass
                     py_TypeInfo* ti = c11__at(py_TypeInfo, &self->types, py_totype(TOP()));
                     if(ti->base != tp_object) {
-                        // PyTypeInfo* base_ti = &_all_types[ti->base];
                         py_TypeInfo* base_ti = c11__at(py_TypeInfo, &self->types, ti->base);
                         if(base_ti->on_end_subclass) base_ti->on_end_subclass(ti);
                     }
diff --git a/src2/example.c b/src2/example.c
new file mode 100644
index 00000000..10fa7ada
--- /dev/null
+++ b/src2/example.c
@@ -0,0 +1,57 @@
+#include "pocketpy.h"
+#include <stdio.h>
+
+static bool int_add(int argc, py_Ref argv) {
+    PY_CHECK_ARGC(2);
+    PY_CHECK_ARG_TYPE(0, tp_int);
+    PY_CHECK_ARG_TYPE(1, tp_int);
+    py_i64 a = py_toint(py_arg(0));
+    py_i64 b = py_toint(py_arg(1));
+    py_newint(py_retval(), a + b);
+    return true;
+}
+
+int main() {
+    // Initialize pocketpy
+    py_initialize();
+
+    // Hello world!
+    bool ok = py_exec("print('Hello world!')", "<string>", EXEC_MODE, NULL);
+    if(!ok) goto __ERROR;
+
+    // Create a list: [1, 2, 3]
+    py_Ref r0 = py_getreg(0);
+    py_newlistn(r0, 3);
+    py_newint(py_list_getitem(r0, 0), 1);
+    py_newint(py_list_getitem(r0, 1), 2);
+    py_newint(py_list_getitem(r0, 2), 3);
+
+    // Eval the sum of the list
+    py_Ref f_sum = py_getbuiltin(py_name("sum"));
+    py_push(f_sum);
+    py_pushnil();
+    py_push(r0);
+    ok = py_vectorcall(1, 0);
+    if(!ok) goto __ERROR;
+
+    printf("Sum of the list: %d\n", (int)py_toint(py_retval()));  // 6
+
+    // Bind native `int_add` as a global variable
+    py_newnativefunc(r0, int_add);
+    py_setglobal(py_name("add"), r0);
+
+    // Call `add` in python
+    ok = py_exec("add(3, 7)", "<string>", EVAL_MODE, NULL);
+    if(!ok) goto __ERROR;
+
+    py_i64 res = py_toint(py_retval());
+    printf("Sum of 2 variables: %d\n", (int)res);  // 10
+
+    py_finalize();
+    return 0;
+
+__ERROR:
+    py_printexc();
+    py_finalize();
+    return 1;
+}
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