updated from atlas

control/coroaverager0.py

@@ -4,7 +4,6 @@ A coroutine to compute a running average
 
     >>> coro_avg = averager()  # <1>
     >>> next(coro_avg)  # <2>
-    0.0
     >>> coro_avg.send(10)  # <3>
     10.0
     >>> coro_avg.send(30)
@@ -15,8 +14,9 @@ A coroutine to compute a running average
 """
 
 def averager():
-    total = average = 0.0
+    total = 0.0
     count = 0
+    average = None
     while True:
         term = yield average  # <4>
         total += term