updated from Atlas

attic/decorators/average_broken.py

@@ -0,0 +1,20 @@
+"""
+>>> avg = make_averager()
+>>> avg(10)
+Traceback (most recent call last):
+  ...
+UnboundLocalError: local variable 'num_items' referenced before assignment
+
+"""
+
+
+def make_averager():
+    num_items = 0
+    total = 0
+
+    def averager(new_value):
+        num_items += 1
+        total += new_value
+        return total / num_items
+
+    return averager