code: def test_empty_input_for_insert(self):
      texts = ["", "           "]
      augs = [nac.RandomCharAug(action="insert")]
  
      for aug in augs:
          for text in texts:
              augmented_data = aug.augment(text)
              self.assertTrue(
                  len(augmented_data) == 0
                  or augmented_data[0].strip() == ""
              )
  
          augmented_texts = aug.augment(texts)
          for augmented_text in augmented_texts:
              self.assertTrue(
                  len(augmented_text) == 0
                  or augmented_text.strip() == ""
              )
  
file_path: nlpaug/test/augmenter/char/test_char.py
imports: import unittest
  import nlpaug.augmenter.char
  import nlpaug.util.text.tokenizer
  from nlpaug.util import Action
label_desc: Use image node_id 10 for calling the TestCharacter obj's underlying member method code with example usage: obj.test_empty_input_for_insert() without return types