docs: def generate_random_string(size=6, chars=string.ascii_uppercase + string.digits):
      """Generate random string.
  
      :param size: Length of the returned string. Default is 6.
      :param chars: List of the usable characters. Default is string.ascii_uppercase + string.digits.
      :type size: int
      :type chars: str
      :return: The random string.
      :rtype: str
      """
      return ''.join(random.choice(chars) for _ in range(size))