code: def test_special_character(self):
      text = "a\tb"
      actual = text_normalize(text)
      expected = "a b"
      self.assertEqual(expected, actual)
  
imports: from unittest import TestCase
  from underthesea import text_normalize
label_desc: Use image node_id 2 for calling the TestTextNormalize obj's underlying member method code with example usage: obj.test_special_character() without return types