Build a subclass of `MappingJSONDecoder`.
        :return: the built subclass

def build(self) -> type:
        """
        Build a subclass of `MappingJSONDecoder`.
        :return: the built subclass
        """
        def _get_property_mappings(encoder: MappingJSONEncoder) -> List[JsonPropertyMapping]:
            return _get_all_property_mappings(encoder, self.mappings, self.superclasses)

        def get_deserializable_cls(decoder: MappingJSONDecoder) -> type:
            return self.target_cls

        return type(
            "%sDynamicMappingJSONDecoder" % self.target_cls.__name__,
            self.superclasses,
            {
                "_get_property_mappings": _get_property_mappings,
                "_get_deserializable_cls": get_deserializable_cls
            }
        )