import tensorflow as tf

    'A flag to override the data format used in the model. channels_first '
    'provides a performance boost on GPU but is not always compatible '
    'with CPU. If left unspecified, the data format will be chosen '
    'automatically based on whether TensorFlow was built for CPU or GPU.')
# optimizer related configuration
tf.app.flags.DEFINE_integer(
    'tf_random_seed', 20180417, 'Random seed for TensorFlow initializers.')
tf.app.flags.DEFINE_float(
    'weight_decay', 1e-5, 'The weight decay on the model weights.')
tf.app.flags.DEFINE_float(
