class Service {
  constructor(db, cache) {
    this.db = db;
    this.cache = cache;
  }

  save(k) { this.db.write(k); }

  load(k) { return this.db.read(k); }

  put(k) { this.cache.set(k); }

  evict(k) { this.cache.drop(k); }
}
