https://github.com/tensorflow/tpu/issues/1687
https://github.com/tensorflow/tpu/issues/1687
https://github.com/tensorflow/tpu/issues/1687
https://github.com/tensorflow/tpu/issues/1687
https://github.com/tensorflow/tpu/issues/1687
https://github.com/tensorflow/tpu/issues/1687
https://github.com/tensorflow/tpu/issues/1687
https://github.com/tensorflow/tpu/issues/1687
https://github.com/tensorflow/tpu/issues/1687
https://github.com/tensorflow/tpu/issues/1687