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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_response_record(self, item_record_type):
 """Gets the response record corresponding to the given ``Item`` record ``Type``. This method is used to retrieve an object implementing the requested record. The ``item_record_type`` may be the ``Type`` returned in ``get_record_types()`` or any of its parents in a ``Type`` hierarchy where ``has_record_type(item_record_type)`` is ``true`` . arg: item_record_type (osid.type.Type):
 an item record type return: (osid.assessment.records.ResponseRecord) - the response record raise: NullArgument - ``item_record_type`` is ``null`` raise: OperationFailed - unable to complete request raise: Unsupported - ``has_record_type(item_record_type)`` is ``false`` *compliance: mandatory -- This method must be implemented.* """

        if not self.has_record_type(item_record_type):
            raise errors.Unsupported()
        if str(item_record_type) not in self._records:
            raise errors.Unimplemented()
        return self._records[str(item_record_type)]