code: def test_forward_cpu(self):
      self._test_forward(gpu=-1)
  
file_path: pfrl/tests/nn_tests/test_recurrent_branched.py
imports: import unittest
  import pytest
  import torch
  from torch import nn
  from pfrl.nn import RecurrentBranched, RecurrentSequential
  from pfrl.testing import torch_assert_allclose
  from pfrl.utils.recurrent import concatenate_recurrent_states, get_recurrent_state_at, mask_recurrent_state_at, one_step_forward
label_desc: Use image node_id 3 for calling the TestRecurrentBranched obj's underlying member method code with example usage: obj.test_forward_cpu() without return types