def message_definition(cls):
    try:
      return cls._message_definition()
    except AttributeError:
      return None
Return fully qualified (Clark notation) tagname corresponding to
dataset/ETHPy150Open AppScale/appscale/AppServer/lib/protorpc/protorpc/messages.py/_DefinitionClass.message_definition--crossover with--dataset/ETHPy150Open scanny/python-pptx/lab/parse_xsd/parse_xsd.py/qtag