How to use the mashumaro.abc.SerializableMapping function in mashumaro

self.x = ChainMap()

    @classmethod
    def from_maps(cls, maps: List[Mapping]):
        inst = cls()
        inst.x = ChainMap(*maps)
        return inst

    def to_maps(self):
        return self.x.maps

    def __repr__(self):
        return f"CustomSerializableChainMap({str(self.x)})"


class CustomSerializableMapping(dict, SerializableMapping):
    def __init__(self):
        super().__init__()
        self.x = {}

    @classmethod
    def from_mapping(cls, mapping):
        inst = cls()
        inst.x = {**mapping}
        return inst

    def to_mapping(self):
        return self.x

    def __repr__(self):
        return f"CustomSerializableMapping({str(self.x)})"