the output tensor having 1 fewer dimension than "input".
Parameters:
      * input (Tensor) -- the input tensor.
  * **dim** (*int*) -- the dimension to reduce.

  * **keepdim** (*bool*) -- whether the output tensor has "dim"
    retained or not.

Keyword Arguments:
      out (Tensor, optional) -- the output tensor.
Example:
  >>> a = torch.randn(4, 2) < 0
  >>> a
  tensor([[ True,  True],
          [False,  True],
          [ True,  True],
          [False, False]])
  >>> torch.any(a, 1)
  tensor([ True,  True,  True, False])
  >>> torch.any(a, 0)
  tensor([True, True])
