https://github.com/tensorflow/tpu/issues/1683
https://github.com/tensorflow/tpu/issues/1683
https://github.com/tensorflow/tpu/issues/1683
https://github.com/tensorflow/tpu/issues/1683
https://github.com/tensorflow/tpu/issues/1683
https://github.com/tensorflow/tpu/issues/1683
https://github.com/tensorflow/tpu/issues/1683
https://github.com/tensorflow/tpu/issues/1683