code: def test_forward_list(self):
      packer = UnpackState(keys=[torchbearer.Y_TRUE])
      state = self.reset_state()
  
      state[torchbearer.Y_PRED] = [1, 2, 3]
      packer.on_forward(state)
      self.assertTrue(state[torchbearer.Y_PRED] == [1, 2, 3])
  
      state = self.reset_state()
  
      state[torchbearer.Y_PRED] = [1, 2, 3]
      packer.on_forward_validation(state)
      self.assertTrue(state[torchbearer.Y_PRED] == [1, 2, 3])
  
file_path: torchbearer/tests/callbacks/test_unpack_state.py
imports: import torch
  from unittest import TestCase
  from mock import MagicMock, patch
  import torchbearer
  from torchbearer.callbacks import UnpackState
label_desc: Use image node_id 6 for calling the TestUnpackState obj's underlying member method code with example usage: obj.test_forward_list() without return types