I guess you are using this repo 24.
The error might be due to a mismatch of your PyTorch version. Although they state PyTorch 0.3+ should work, the last update was 6 months ago.
I’m not familiar with the repo, but you could try to create a conda environment with PyTorch 0.3 just to try, if it runs. Have a look here 15 for more information on conda envs.