First of all thank you very much for the great work 
installing pytorch 1.3.0 via pip in Windows 10 fails with

ERROR: Could not find a version that satisfies the requirement torch>=1.1.0 (from flair==0.4.4->-r requirements.txt (line 30)) (from versions: 0.1.2, 0.1.2.post1, 0.1.2.post2)
ERROR: No matching distribution found for torch>=1.1.0 (from flair==0.4.4->-r requirements.txt (line 30))

I fixed it by downloading and installing the wheel manually from https://download.pytorch.org/whl/torch_stable.html 504
The reason pip can not find it is in the URL:
https://download.pytorch.org/whl/cpu/torch-1.3.0%2Bcpu-cp36-cp36m-win_amd64.whl 195
The %2B somehow snuck in there and breaks pip’s lookup mechanism. It only occurs for some versions, not all of them.