seems like \"import tensorflow as tf\" directly raise this error
Colab link:https://colab.research.google.com/drive/1Jr0j_I_npKQxcQ1ggJQFHTqoJHmt9Bqk
sorry, the problem is that installing tensorflow-gpu does not uninstall tensorflow and tensorflow 2.2.0 has introduced some changes that are incompatible with tensorflow 1.14.0.
if you do
%tensorflow_version 2.x !pip uninstall -y tensorflow !pip install tensorflow-gpu==1.14.0
it will work