class_docstr: Test CLIP4Clip model
code: def test_token(self):
      text = "hello world"
      text_tokens = clip4clip.tokenize(text)
      self.assertEqual(text_tokens, ["hello</w>", "world</w>"])
  
file_path: towhee/tests/unittests/models/clip4clip/test_clip4clip.py
imports: import unittest
  import torch
  import numpy
  from towhee.models.clip import SimpleTokenizer
  from towhee.models.clip4clip import convert_tokens_to_id
  from towhee.models.clip4clip import create_model
  from towhee.models import clip4clip
label_desc: Use image node_id 2 for calling the TestCLIP4Clip obj's underlying member method code with example usage: obj.test_token() without return types