Torch.utils.data issue with v1.7

It seems the call from torch.utils.data import * is broken in v1.7 while working in v1.6. Is this desired?

>>> print(torch.__version__)
1.7.0
>>> from torch.utils.data import *
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
AttributeError: module 'torch.utils.data' has no attribute 'BatchSamplerDistributedSamplerDataset'

This PR unfortunately broke the star import by forgetting to add commas between the class names.
However, it’s already fixed in the nightly binaries so you could update if you need to use this way of importing the classes.
Note that importing or using the classes directly e.g. via:

from torch.utils.data import BatchSampler

would still work.