@abc.abstractmethod<EOL><INDENT>def get_agent_lookup_session_for_agency(self, agency_id):<DEDENT>
return<EOL>
Gets the ``OsidSession`` associated with the agent lookup service for the given agency.

        :param agency_id: the ``Id`` of the agency
        :type agency_id: ``osid.id.Id``
        :return: ``an _agent_lookup_session``
        :rtype: ``osid.authentication.AgentLookupSession``
        :raise: ``NotFound`` -- ``agency_id`` not found
        :raise: ``NullArgument`` -- ``agency_id`` is ``null``
        :raise: ``OperationFailed`` -- ``unable to complete request``
        :raise: ``Unimplemented`` -- ``supports_agent_lookup()`` or ``supports_visible_federation()`` is ``false``

        *compliance: optional -- This method must be implemented if
        ``supports_agent_lookup()`` and
        ``supports_visible_federation()`` are ``true``.*