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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_part_bank_assignment_session(self):
 """Gets the ``OsidSession`` associated with assigning assessment part to bank. return: (osid.assessment.authoring.AssessmentPartBankAssignmentS ession) - an ``AssessmentPartBankAssignmentSession`` raise: OperationFailed - unable to complete request raise: Unimplemented - ``supports_assessment_part_bank_assignment()`` is ``false`` *compliance: optional -- This method must be implemented if ``supports_assessment_part_bank_assignment()`` is ``true``.* """

        if not self.supports_assessment_part_bank_assignment():
            raise errors.Unimplemented()
        # pylint: disable=no-member
        return sessions.AssessmentPartBankAssignmentSession(runtime=self._runtime)