https://github.com/tensorflow/tpu/issues/1682
https://github.com/tensorflow/tpu/issues/1682
https://github.com/tensorflow/tpu/issues/1682
https://github.com/tensorflow/tpu/issues/1682
https://github.com/tensorflow/tpu/issues/1682
https://github.com/tensorflow/tpu/issues/1682
https://github.com/tensorflow/tpu/issues/1682
https://github.com/tensorflow/tpu/issues/1682