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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_bank_admin_session(self):
 """Gets the OsidSession associated with the bank administration service. return: (osid.assessment.BankAdminSession) - a ``BankAdminSession`` raise: OperationFailed - unable to complete request raise: Unimplemented - ``supports_bank_admin() is false`` *compliance: optional -- This method must be implemented if ``supports_bank_admin()`` is true.* """

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