code: def plaintext(cls):
          
          builtin_mechs = cls._get_builtin_mechanisms()
          plaintext_mechs = [mech for _, mech in builtin_mechs.items()
                             if mech.insecure and mech.priority is not None]
          return SASLAuth(plaintext_mechs)
docs: Uses only authentication mechanisms that provide the credentials in
          un-hashed form, typically meaning
          :attr:`~pysasl.AuthenticationCredentials.has_secret` is True.
  
          Returns:
              A new :class:`SASLAuth` object.