docs: function Cache(options) {
    options = options || {};
  
    if (!(this instanceof Cache)) {
      return new Cache(options);
    }
  
    if (typeof options === 'function'){
      options = { store: options };
    }
  
    _.defaults(options, defaults);
    var Store = options.store;
  
    this.ttl = options.ttl;
    this.tti = options.tti;
    this.store = new Store(options);
    this.stats = new CacheStats();
  }