code: def expander(x, factor: int = 2):
      return x * factor
  
file_path: opacus/opacus/tests/grad_samples/common.py
imports: import unittest
  from typing import Tuple, Union
  import torch
  import torch.nn
  import torch.nn.functional
  from opacus.utils.per_sample_gradients_utils import compute_grad_samples_microbatch_and_opacus, compute_opacus_grad_sample, is_batch_empty
  from torch.nn.utils.rnn import PackedSequence
  from torch.testing import assert_close
label_desc: Use image node_id 1 for calling a global function with example usage: expander(x, factor) and returns: unknown