code: def identity_fn(x: Union[torch.Tensor, list]) -> torch.Tensor:
      if isinstance(x, list):
          return torch.from_numpy(np.array(x))
      else:
          return x
  
file_path: alibi-detect/alibi_detect/cd/pytorch/tests/test_classifier_pt.py
imports: from itertools import product
  import numpy
  import pytest
  import torch
  import torch.nn
  from typing import Union
  from alibi_detect.cd.pytorch.classifier import ClassifierDriftTorch
label_desc: Use image node_id 1 for calling a global function with example usage: identity_fn(x) and returns: torch, x