Fix small typo in docstring

Signed-off-by: Iustin Pop <iustin@google.com>
Reviewed-by: Michael Hanselmann <hansmi@google.com>

lib/utils/algo.py

@@ -119,7 +119,7 @@ def InvertDict(dict_in):
   """Inverts the key/value mapping of a dict.
 
   @param dict_in: The dict to invert
-  @returns the inverted dict
+  @return: the inverted dict
 
   """
   return dict(zip(dict_in.values(), dict_in.keys()))