def get_agent_agency_session(self):
raise Unimplemented()<EOL>
Gets the session for retrieving agent to agency mappings.

        return: (osid.authentication.AgentAgencySession) - an
                ``AgentAgencySession``
        raise:  OperationFailed - unable to complete request
        raise:  Unimplemented - ``supports_agent_agency()`` is ``false``
        *compliance: optional -- This method must be implemented if
        ``supports_agent_agency()`` is ``true``.*