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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 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'])