docs: def get_agent_lookup_session(self):
          """Gets the ``OsidSession`` associated with the agent lookup service.
  
          return: (osid.authentication.AgentLookupSession) - an
                  ``AgentLookupSession``
          raise:  OperationFailed - unable to complete request
          raise:  Unimplemented - ``supports_agent_lookup()`` is ``false``
          *compliance: optional -- This method must be implemented if
          ``supports_agent_lookup()`` is ``true``.*
  
          """
          if not self.supports_agent_lookup():
              raise errors.Unimplemented()
          # pylint: disable=no-member
          return sessions.AgentLookupSession(runtime=self._runtime)