# Taken partially from https://github.com/kennknowles/python-either
from abc import ABC, abstractmethod


class Either(ABC):
    def __init__(self, v):
        self._v = v

    @property
    def value(self):
        return self._v

    @property
    @abstractmethod
    def is_left(self):
        pass

    @property
    @abstractmethod
    def is_right(self):
        pass


class Left(Either):
    @property
    def is_left(self):
        return True

    @property
    def is_right(self):
        return False


class Right(Either):
    @property
    def is_left(self):
        return False

    @property
    def is_right(self):
        return True