message: Add test for stacked "for_subclass_implementers" in class __mro__.
  This test asserts that "for_subclass_implementers" short-circuits the __mro__ inspection.
  A method labeled "for_subclass_implementers" will be documented in it's defining class, regardless of inheritable decorations farther up the class hierarchy.
diff: @@ -145,7 +145,7 @@ class DocControlsTest(googletest.TestCase):
  self.assertTrue(
  doc_controls.should_skip_class_attr(GrandChild, 'my_method'))
  - def testfor_subclass_implementers(self):
  + def test_for_subclass_implementers(self):
  class GrandParent(object):
  @@ -178,6 +178,43 @@ class DocControlsTest(googletest.TestCase):
  self.assertTrue(
  doc_controls.should_skip_class_attr(Grand2Child, 'my_method'))
  + def test_for_subclass_implementers_short_circuit(self):
  +
  + class GrandParent(object):
  +
  + @doc_controls.for_subclass_implementers
  + def my_method(self):
  + pass
  +
  + class Parent(GrandParent):
  +
  + def my_method(self):
  + pass
  +
  + class Child(Parent):
  +
  + @doc_controls.do_not_doc_inheritable
  + def my_method(self):
  + pass
  +
  + class GrandChild(Child):
  +
  + @doc_controls.for_subclass_implementers
  + def my_method(self):
  + pass
  +
  + class Grand2Child(Child):
  + pass
  +
  + self.assertFalse(
  + doc_controls.should_skip_class_attr(GrandParent, 'my_method'))
  + self.assertTrue(doc_controls.should_skip_class_attr(Parent, 'my_method'))
  + self.assertTrue(doc_controls.should_skip_class_attr(Child, 'my_method'))
  + self.assertFalse(
  + doc_controls.should_skip_class_attr(GrandChild, 'my_method'))
  + self.assertTrue(
  + doc_controls.should_skip_class_attr(Grand2Child, 'my_method'))
  +
  if __name__ == '__main__':
  googletest.main()
  