export declare class EmptySet { get size(): number; add(value: T): this; clear(): void; delete(value: T): boolean; forEach(callbackfn: (value: T, value2: T, set: Set) => void, thisArg?: any): void; has(value: T): boolean; [Symbol.iterator](): EmptySetIterator; entries(): EmptySetIterator<[T, T]>; keys(): EmptySetIterator; values(): EmptySetIterator; get [Symbol.toStringTag](): string; } declare class EmptySetIterator { [Symbol.iterator](): this; next(): { done: boolean; value: null; }; } export {};