Update example: Counter.subtract returns None, not self

asvetlov · asvetlov · commit f635172c7222 · 2012-12-17T14:01:16.000+02:00
diff --git a/Doc/library/collections.rst b/Doc/library/collections.rst
@@ -121,6 +121,7 @@ For example::
             >>> c = Counter(a=4, b=2, c=0, d=-2)
             >>> d = Counter(a=1, b=2, c=3, d=4)
             >>> c.subtract(d)
+            >>> c
             Counter({'a': 3, 'b': 0, 'c': -3, 'd': -6})
 
       .. versionadded:: 3.2
