human
Solve the following python programming problem given the following code:
@connect_on_app_finalize
def add_backend_cleanup_task(app):
assistant
#Here is the Python program you requested.

    """Task used to clean up expired results.
    If the configured backend requires periodic cleanup this task is also
    automatically configured to run every day at 4am (requires
    :program:`celery beat` to be running).
    """
    @app.task(name=u'celery.backend_cleanup', shared=False, lazy=False)
    def backend_cleanup():
        app.backend.cleanup()
    return backend_cleanup