code: def test_candidates(self):
      candidates = ["AAA", "11", "===", "中文"]
      text = "quick brown jumps over lazy"
      aug = RandomCharAug(min_char=4, candidates=candidates)
      augmented_data = aug.augment(text)
      augmented_text = augmented_data[0]
      self.assertNotEqual(text, augmented_text)
  
      match = False
      for c in candidates:
          if c in augmented_text:
              match = True
              break
  
      self.assertTrue(match)
  
file_path: nlpaug/test/augmenter/char/test_random_char.py
imports: import unittest
  from nlpaug.augmenter.char.random import RandomCharAug
label_desc: Use image node_id 10 for calling the TestRandomCharReplaceAug obj's underlying member method code with example usage: obj.test_candidates() without return types