from abc import ABC, abstractmethod


class Storage(ABC):
    @abstractmethod
    def save(self, key: str, value: str) -> None:
        pass

    @abstractmethod
    def load(self, key: str) -> str:
        pass


class MemoryStorage(Storage):
    def __init__(self):
        self.storage = {}

    def save(self, key: str, value: str) -> None:
        self.storage[key] = value

    def load(self, key: str) -> str:
        return self.storage[key]