Hey @xerxex, which version of PyTorch are you using?
  File "/data/anaconda3/lib/python3.7/site-packages/torch/distributed/rpc/__init__.py", line 60, in init_rpc
    init_method, rank=rank, world_size=world_size

Given this line above, it does seem to be v1.4 nor the current master branch 2.
RPC is only available since v1.4.