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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_authorization_session(self):
 """Gets an ``AuthorizationSession`` which is responsible for performing authorization checks. return: (osid.authorization.AuthorizationSession) - an authorization session for this service raise: OperationFailed - unable to complete request raise: Unimplemented - ``supports_authorization()`` is ``false`` *compliance: optional -- This method must be implemented if ``supports_authorization()`` is ``true``.* """

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