from .model import model

class single_set_model(model):
    content = NotImplemented

    def _single_validator(self) -> callable:
        raise NotImplementedError()

    def _validators(self) -> dict:
        return {
            "content": self._single_validator()
        }

    def __new__(cls, *args, **kwargs) -> object:
        if cls.content == NotImplemented:
            raise NotImplementedError("Attribute content must be field.")

        super().__new__(*args, **kwargs)

    def __repr__(self) -> str:
        return type(self).__name__ + ": \"" + str(self) + "\""

    def __str__(self) -> str:
        return self.content