diff --git a/cookbook/c07/p12_closure_access.py b/cookbook/c07/p12_closure_access.py
index cc51c3f..cab3e27 100644
--- a/cookbook/c07/p12_closure_access.py
+++ b/cookbook/c07/p12_closure_access.py
@@ -29,3 +29,38 @@ f = sample()
 f()
 f.set_n(10)
 f()
+
+import sys
+class ClosureInstance:
+    def __init__(self, locals=None):
+        if locals is None:
+            locals = sys._getframe(1).f_locals
+
+        # Update instance dictionary with callables
+        self.__dict__.update((key,value) for key, value in locals.items()
+                            if callable(value) )
+    # Redirect special methods
+    def __len__(self):
+        return self.__dict__['__len__']()
+
+# Example use
+def Stack():
+    items = []
+    def push(item):
+        items.append(item)
+
+    def pop():
+        return items.pop()
+
+    def __len__():
+        return len(items)
+
+    return ClosureInstance()
+
+s = Stack()
+print(s)
+s.push(10)
+s.push(20)
+print(len(s))
+print(s.pop())
+print(s.pop())