old_contents: import pandas as pd
  import torch
  from torch import as_tensor,Tensor,ByteTensor,LongTensor,FloatTensor,HalfTensor,DoubleTensor
  import torch.nn as nn
  import torch.nn.functional as F
  from torch.utils.data import SequentialSampler,RandomSampler,Sampler,BatchSampler
  from torch.utils.data import IterableDataset,get_worker_info
  from torch.utils.data._utils.collate import default_collate,default_convert
  
  
new_contents: import pandas as pd
  import torch
  from torch import as_tensor,Tensor,ByteTensor,LongTensor,FloatTensor,HalfTensor,DoubleTensor
  import torch.nn as nn
  import torch.nn.functional as F
  from torch.utils.data import SequentialSampler,RandomSampler,Sampler,BatchSampler
  from torch.utils.data import IterableDataset,get_worker_info
  from torch.utils.data._utils.collate import default_collate,default_convert
  
  # Python 3.8 changed to 'spawn' but that doesn't work with PyTorch DataLoader w n_workers>0
  import platform
  if platform.system()=='Darwin': multiprocessing.set_start_method('fork', force=True)
  
  
subject: use fork multiprocessing on mac h/t aseifert