NOTE: This code has moved to
https://github.com/tensorflow/hub/tree/master/examples/image_retraining

retrain.py is an example script that shows how one can adapt a pretrained
network for other classification problems (including use with TFLite and
quantization).

As of TensorFlow 1.7, it is recommended to use a pretrained network from
TensorFlow Hub, using the new version of this example found in the location
above, as explained in TensorFlow's revised image retraining
tutorial.

Older versions of this example (using frozen GraphDefs instead of
TensorFlow Hub modules) are available in the release branches of
TensorFlow versions up to and including 1.7.