docs: def deserialize(self, info, method="urlencoded", **kwargs):
          """
          Convert from an external representation to an internal.
          
          :param info: The input  
          :param method: The method used to deserialize the info
          :param kwargs: extra Keyword arguments
          :return: In the normal case the Message instance
          """
          try:
              func = getattr(self, "from_%s" % method)
          except AttributeError:
              raise FormatError("Unknown serialization method (%s)" % method)
          else:
              return func(info, **kwargs)