clear() {
        this.store.clear();
        this.size = this.store.size;
        return this;
    }
/**
     *  clears all keys and values from the store and sets size to 0
     *  @time O(1)
     *  @return {LRUCache} this instance
     */
clears all keys and values from the store and sets size to 0
@time O(1)
@return {LRUCache} this instance
clears all keys and values from the store and sets size to 0 @time O ( 1 ) @return { LRUCache } this instance
clear() {
        this.store.clear();
        this.size = this.store.size;
        return this;
    }
clear ( ) { this . store . clear ( ) ; this . size = this . store . size ; return this ; }
clears all keys and values from the store and sets size to 0
  @time O(1)
  @return {LRUCache} this instance
clears all keys and values from the store and sets size to 0 @time O ( 1 ) @return { LRUCache } this instance