TypeError: '_FlagValues' object is not iterable

Traceback (most recent call last):
File "main.py", line 147, in
tf.app.run()
File "/root/anaconda3/envs/tensorflow/lib/python3.6/site-packages/tensorflow/python/platform/app.py", line 48, in run
_sys.exit(main(_sys.argv[:1] + flags_passthrough))
File "main.py", line 70, in main
flags_dict = {k:FLAGS[k].value for k in FLAGS}
TypeError: '_FlagValues' object is not iterable

my input :python main.py --input_height 96 --input_width 96 --output_height 48 --output_width 48 --dataset anime --crop --train --epoch 300 --input_fname_pattern ".jpg"
so,what's the problem???