MR.87

I copy all codes from [hparams demo colab](https://colab.research.google.com/github/tensorflow/tensorboard/blob/master/docs/hyperparameter_tuning_with_hparams.ipynb#scrollTo=lEWCCQYkWIdA) And run my TB 2.19 than encounter this problem But it works fine on colab (TB 2.18)