def get_model(self, model_name):
        self.check_models_ready()
        try:
            return self.models[model_name.lower()]
        except KeyError:
            raise LookupError(
                "App '%s' doesn't have a '%s' model." % (self.label, model_name))
Ask master server for mapping.
dataset/ETHPy150Open django/django/django/apps/config.py/AppConfig.get_model--crossover with--dataset/ETHPy150Open google/grr/grr/server/data_server/data_server.py/StandardDataServer.RenewMapping