updated contents from Atlas repo

decorators/average_fixed.py

@@ -0,0 +1,45 @@
+"""
+>>> avg = make_averager()
+>>> other_avg = make_averager()
+>>> avg(10)
+10.0
+>>> avg(11)
+10.5
+>>> avg(12)
+11.0
+>>> avg.__code__.co_varnames
+('new_value',)
+>>> avg.__code__.co_freevars
+('num_items', 'total')
+>>> avg.__closure__  # doctest: +ELLIPSIS
+(<cell at 0x...: int object at 0x...>, <cell at 0x...: int object at 0x...>)
+>>> avg.__closure__[0].cell_contents
+3
+>>> avg.__closure__[1].cell_contents
+33
+>>> other_avg(5)
+5.0
+>>> other_avg(10)
+7.5
+>>> other_avg(15)
+10.0
+"""
+
+DEMO = """
+>>> avg.__closure__
+(<cell at 0x10fd24f78: int object at 0x10f6d3db0>,
+ <cell at 0x10fd24d38: int object at 0x10f6d4170>)
+"""
+
+
+def make_averager():
+    num_items = 0
+    total = 0
+
+    def averager(new_value):
+        nonlocal num_items, total
+        num_items += 1
+        total += new_value
+        return total / num_items
+
+    return averager