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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_assessment_notification_session(self, assessment_receiver):
 """Gets the notification session for notifications pertaining to assessment changes. arg: assessment_receiver (osid.assessment.AssessmentReceiver):
 the assessment receiver interface return: (osid.assessment.AssessmentNotificationSession) - an ``AssessmentNotificationSession`` raise: NullArgument - ``assessment_receiver`` is ``null`` raise: OperationFailed - unable to complete request raise: Unimplemented - ``supports_assessment_notification()`` is ``false`` *compliance: optional -- This method must be implemented if ``supports_assessment_notification()`` is ``true``.* """

        if not self.supports_assessment_notification():
            raise errors.Unimplemented()
        # pylint: disable=no-member
        return sessions.ItemNotificationSession(runtime=self._runtime, receiver=assessment_receiver)