code: def _validate_params(params_list, fn):
      ref_params = params_list[0]
      for param_list in params_list[1:]:
          for p1, p2 in zip(ref_params, param_list):
              fn(p1, p2)
  
file_path: pytorch/test/distributed/optim/test_apply_optimizer_in_backward.py
imports: import unittest
  from copy import deepcopy
  import torch
  import torch.nn
  from torch.distributed.optim import _apply_optimizer_in_backward, _get_in_backward_optimizers
label_desc: Use image node_id 1 for calling a global function with example usage: _validate_params(params_list, fn) without return types