File "generate_tfrecord.py", line 23, in <module> flags = tf.app.flags AttributeError: module 'tensorflow' has no attribute 'app'

When running generate_tfrecord.py, encounter this issue on File "generate_tfrecord.py", line 23, in
flags = tf.app.flags
AttributeError: module 'tensorflow' has no attribute 'app'.

Any advice?