NameError: name '_C' is not defined: (Prototype) Use iOS GPU in PyTorch (Metal)

Mobile
4

Thank you, @xta0, but I struggle to import Metal PyTorch torch==1.9.0a0+gite442d5c
(after fixing the compilation error)
Error near import torch when I try to run my model:

Traceback (most recent call last):
  File "/demo.py", line 14, in <module>
    import torch
  File "/opt/anaconda3/envs/FOM_METAL/lib/python3.8/site-packages/torch/__init__.py", line 228, in <module>
    __all__ += [name for name in dir(_C)
NameError: name '_C' is not defined

Error in python console:

python
>>> import torch

  File "/opt/anaconda3/envs/FOM_METAL/lib/python3.8/site-packages/torch/_tensor.py", line 322, in Tensor
    detach = _C._add_docstr(_C._TensorBase.detach, r"""
RuntimeError: method 'detach' already has a docstring

torch 1.8.0 works fine

I have no clue how to fix this.