class_docstr: Test layer freezer
code: def test_freezer_all(self):
      self.freezer.set_all()
      res = []
      for i in range(len(self.freezer.layer_names)):
          r = self.freezer.status(i)
          for x in r:
              res.append(x)
      self.assertEqual(res, ["frozen" for _ in range(len(res))])
  
      self.freezer.set_all(freeze=False)
      res = []
      for i in range(len(self.freezer.layer_names)):
          r = self.freezer.status(i)
          for x in r:
              res.append(x)
      self.assertEqual(res, ["unfrozen" for _ in range(len(res))])
  
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 4 for calling the TestFreezer obj's underlying member method code with example usage: obj.test_freezer_all() without return types