code: def test_no_text(self):
      text = ""
      actual = sentiment(text)
      expected = None
      self.assertEqual(actual, expected)
  
file_path: underthesea/tests/pipeline/sentiment/test_bank.py
imports: from unittest import TestCase
  from underthesea.pipeline.sentiment import sentiment
label_desc: Use image node_id 1 for calling the TestSentiment obj's underlying member method code with example usage: obj.test_no_text() without return types