Also Fixes Depreciation Userwarning below
torchaudio/torchaudio/functional.py:124: UserWarning: istft has been moved to PyTorch and will be deprecated, please use torch.istft instead.
by replacing torchaudio.functional.istft() with torch.istft() instead.
Fixes pheepa/DCUnet/issues/2
Also Fixes Depreciation Userwarning below
torchaudio/torchaudio/functional.py:124: UserWarning: istft has been moved to PyTorch and will be deprecated, please use torch.istft instead.
by replacing torchaudio.functional.istft() with torch.istft() instead.