Виктор Лешневский

class Fire:
    def __str__(self):
        return 'Огонь'

    def __add__(self, other):
        if isinstance(other, Aqua):
            return Vapor(part1=self, part2=other)
        elif isinstance(other, Earth):
            return Lava(part1=self, part2=other)
        elif isinstance(other, Air):
            return Lightning(part1=self, part2=other)