docs: def get_grading_agent_id(self):
          """Gets the ``Id`` of the ``Agent`` that created this entry.
  
          return: (osid.id.Id) - the ``Id`` of the ``Agent``
          raise:  IllegalState - ``is_graded()`` is ``false`` or
                  ``is_derived()`` is ``true``
          *compliance: mandatory -- This method must be implemented.*
  
          """
          if not self.is_graded or self.is_derived():
              raise errors.IllegalState()
          return Id(self._my_map['gradingAgentId'])