clean up returnValue calls

master/buildbot/schedulers/forcesched.py

@@ -267,6 +267,7 @@ def force(self, owner, builder_name, **kwargs):
             # for all the builders
             # we just do nothing on a builder that is not in our builderNames
             defer.returnValue(None)
+            return
 
         # Currently the validation code expects all kwargs to be lists
         # I don't want to refactor that now so much sure we comply...

master/docs/developer/style.rst

@@ -139,7 +139,7 @@ The key points to notice here:
   ``return xval + y`` are invalid.  Instead, yield the result of
   ``defer.returnValue``.  Although this function does cause an immediate
   function exit, for clarity it should be followed by a bare ``return``, as in
-  the example.
+  the example, unless it is the last statement in a function.
 
 The great advantage of ``inlineCallbacks`` is that it allows you to use all
 of the usual Pythonic control structures in their natural form. In particular,