class_docstr: Test layer freezer
code: def test_freezer_slice(self):
      self.freezer.set_slice(1)
      res = self.freezer.show_frozen_layers()
      self.assertEqual(res, ["conv1"])
  
file_path: towhee/tests/unittests/trainer/test_freezer.py
imports: import unittest
  import torchvision
  from towhee.trainer.utils.layer_freezer import LayerFreezer
label_desc: Use image node_id 5 for calling the TestFreezer obj's underlying member method code with example usage: obj.test_freezer_slice() without return types