class ConnectionRouter

def allow_migrate(self, db, app_label, **hints)

    def allow_migrate(self, db, app_label, **hints):
        for router in self.routers:
            try:
                method = router.allow_migrate
            except AttributeError:
                # If the router doesn't have a method, skip to the next one.
                continue

            allow = method(db, app_label, **hints)

            if allow is not None:
                return allow
        return True

def allow_migrate_model(self, db, model)

    def allow_migrate_model(self, db, model):
        return self.allow_migrate(
            db,
            model._meta.app_label,
            model_name=model._meta.model_name,
            model=model,
        )

def allow_relation(self, obj1, obj2, **hints)

    def allow_relation(self, obj1, obj2, **hints):
        for router in self.routers:
            try:
                method = router.allow_relation
            except AttributeError:
                # If the router doesn't have a method, skip to the next one.
                pass
            else:
                allow = method(obj1, obj2, **hints)
                if allow is not None:
                    return allow
        return obj1._state.db == obj2._state.db

def db_for_read(self, model, **hints)

        def _route_db(self, model, **hints):
            chosen_db = None
            for router in self.routers:
                try:
                    method = getattr(router, action)
                except AttributeError:
                    # If the router doesn't have a method, skip to the next one.
                    pass
                else:
                    chosen_db = method(model, **hints)
                    if chosen_db:
                        return chosen_db
            instance = hints.get("instance")
            if instance is not None and instance._state.db:
                return instance._state.db
            return DEFAULT_DB_ALIAS

def db_for_write(self, model, **hints)

        def _route_db(self, model, **hints):
            chosen_db = None
            for router in self.routers:
                try:
                    method = getattr(router, action)
                except AttributeError:
                    # If the router doesn't have a method, skip to the next one.
                    pass
                else:
                    chosen_db = method(model, **hints)
                    if chosen_db:
                        return chosen_db
            instance = hints.get("instance")
            if instance is not None and instance._state.db:
                return instance._state.db
            return DEFAULT_DB_ALIAS

def get_migratable_models(self, app_config, db, include_auto_created=False)

Return app models allowed to be migrated on provided db.

    def get_migratable_models(self, app_config, db, include_auto_created=False):
        """Return app models allowed to be migrated on provided db."""
        models = app_config.get_models(include_auto_created=include_auto_created)
        return [model for model in models if self.allow_migrate_model(db, model)]

def routers(self)