docs: def get_rating_id(self):
          """Gets the ``Id`` of the ``Grade``.
  
          return: (osid.id.Id) - the ``Agent``  ``Id``
          raise:  IllegalState - ``has_rating()`` is ``false``
          *compliance: mandatory -- This method must be implemented.*
  
          """
          # Implemented from template for osid.resource.Resource.get_avatar_id_template
          if not bool(self._my_map['ratingId']):
              raise errors.IllegalState('this Comment has no rating')
          else:
              return Id(self._my_map['ratingId'])