def get_single(self, user, project_id, location_id):
        project = Project.objects.as_contributor(user, project_id)
        location = self.get(pk=location_id)
        if not location.private or location.private_for_project == project:
            return location
        else:
            raise PermissionDenied('The location can not be used with this '
                                   'project.')
Flows can send client messages using CallClient().
dataset/ETHPy150Open ExCiteS/geokey/geokey/contributions/managers.py/LocationManager.get_single--crossover with--dataset/ETHPy150Open google/grr/grr/lib/flow_test.py/FlowTest.testCallClient