    def remove_client(self, client_id):
        """Remove a client by its id if it is existed."""
        orm_client = (
            self.db.query(orm.OAuthClient).filter_by(identifier=client_id).one_or_none()
        )
        if orm_client is not None:
            self.db.delete(orm_client)
            self.db.commit()
            app_log.info("Removed client %s", client_id)
        else:
            app_log.warning("No such client %s", client_id)
Remove a client by its id if it is existed.
jupyterhub/oauth/provider.py