code: def test_special_char_lower_case(self):
      model = nmc.Keyboard(
          model_path=self.eng_keyboard_path,
          special_char=True,
          numeric=False,
          upper_case=False,
      )
      mapping = model.model
      for key, values in mapping.items():
          self.assertFalse(re.match("^[0-9]*$", key))
          self.assertGreater(len(values), 0)
          for value in values:
              self.assertFalse(re.match("^[0-9]*$", value))
      self.assertGreater(len(mapping), 0)
  
file_path: nlpaug/test/model/char/test_keyboard_model.py
imports: import unittest
  import re
  import os
  from dotenv import load_dotenv
  import nlpaug.model.char
label_desc: Use image node_id 3 for calling the TestKeyboard obj's underlying member method code with example usage: obj.test_special_char_lower_case() without return types