Use not None to check FLAGS.{saver_max_to_keep,enqueue_max_steps,saver_keep_checkpoint_every_n_hours} for overriding, otherwise, when the flag is set 0, it failed to override.
Use not None to check FLAGS.{saver_max_to_keep,enqueue_max_steps,saver_keep_checkpoint_every_n_hours} for overriding, otherwise, when the flag is set 0, it failed to override.

PiperOrigin-RevId: 280515861

tensorflow/lingvo,tensorflow/lingvo,tensorflow/lingvo,tensorflow/lingvo