code: def is_slug(string, sign='-'):
      
      if not is_full_string(string):
          return False
      rex = r'^([a-z\d]+' + re.escape(sign) + r'?)*[a-z\d]$'
      return re.match(rex, string) is not None
docs: Checks if a given string is a slug.
  
      :param string: String to check.
      :type string: str
      :param sign: Join sign used by the slug.
      :type sign: str
      :return: True if slug, false otherwise.