    def current_user(self):
        """Override .current_user accessor from tornado

        Allows .get_current_user to be async.
        """
        if not hasattr(self, '_jupyterhub_user'):
            raise RuntimeError("Must call async get_current_user first!")
        return self._jupyterhub_user
Override .current_user accessor from tornado

Allows .get_current_user to be async.
jupyterhub/handlers/base.py