code: def sub(a: Tensor, b: Tensor) -> Tensor:
      _0 = get_constants_like(0, a)
      case = (a.isinf() & b.isinf()) & (a == b)
      return torch.where(case, _0, a - b)
  
imports: from __future__ import annotations
  import math
  from typing import Callable, Tuple, Union
  import torch
  from botorch.exceptions import UnsupportedError
  from botorch.utils.constants import get_constants_like
  from torch import finfo, Tensor
  from torch.nn.functional import softplus
label_desc: Use image node_id 4 for calling a global function with example usage: sub(a, b) and returns: torch