class_docstr: Unittest for hub utils.
class_docstr_tok: ["Unittest","for","hub","utils","."]
code: def test_token(self):
      self.assertEqual(hub_file.token, None)
      self.assertEqual(
          hub_file.file, (Path.home() / ".towhee/token").resolve()
      )
      hub_file.set_token("test-token")
      hub_file.save()
      token1 = hub_file.get_token()
      self.assertEqual(token1, "test-token")
      hub_file.delete()
      token2 = hub_file.get_token()
      self.assertEqual(token2, None)
  
imports: import unittest
  from pathlib import Path
  from towhee.utils.hub_file_utils import HubFileUtils
label_desc: Use image node_id 1 for calling the TestHubUtils obj's underlying member method code with example usage: obj.test_token() without return types