torch.promote_types
torch.promote_types(type1, type2) -> dtype
Returns the "torch.dtype" with the smallest size and scalar kind
   that is not smaller nor of lower kind than either type1 or
   type2. See type promotion documentation for more information on
   the type promotion logic.
Parameters:
      * type1 ("torch.dtype") --
  * **type2** ("torch.dtype") --

Example:
  >>> torch.promote_types(torch.int32, torch.float32)
  torch.float32
  >>> torch.promote_types(torch.uint8, torch.long)
  torch.long
