    def delete_forever(self):
        """Called when a user or server is deleted.

        This can do things like request removal of resources such as persistent storage.
        Only called on stopped spawners, and is usually the last action ever taken for the user.

        Will only be called once on each Spawner, immediately prior to removal.

        Stopping a server does *not* call this method.
        """
Called when a user or server is deleted.

This can do things like request removal of resources such as persistent storage.
Only called on stopped spawners, and is usually the last action ever taken for the user.

Will only be called once on each Spawner, immediately prior to removal.

Stopping a server does *not* call this method.
jupyterhub/spawner.py