code: def get_phony(device: torch.device, *, requires_grad: bool) -> Tensor:
      """Gets a phony. Phony is tensor without space. It is useful to make
      arbitrary dependency in a autograd graph because it doesn't require any
      gradient accumulation.
  
      .. note::
  
          Phonies for each device are cached. If an autograd function gets a phony
          internally, the phony must be detached to be returned. Otherwise, the
          autograd engine will mutate the cached phony in-place::
  
              class Phonify(torch.autograd.Function):
                  @staticmethod
                  def forward(ctx, input):
                      phony = get_phony(input.device, requires_grad=False)
                      return phony.detach()  # detach() is necessary.
  
      """
      key = (device, requires_grad)
  
      try:
          phony = _phonies[key]
      except KeyError:
          with use_stream(default_stream(device)):
              # Creating phony with size 1 instead of zero, since currently
              # tensorpipe does not work with tensors of size zero.
              phony = torch.empty(
                  1, device=device, requires_grad=requires_grad
              )
  
          _phonies[key] = phony
  
      return phony
  
imports: from typing import Dict, List, Tuple
  import torch
  from torch import Tensor
  from .stream import default_stream, use_stream
label_desc: Use image node_id 1 for calling a global function with example usage: get_phony(device) and returns: phony