export interface ReadonlyMultiMap<TKey, TValue> {
    keys(): Iterable<TKey>;

    get(key: TKey): Iterable<TValue>;
}

export default class MultiMap<TKey, TValue> implements ReadonlyMultiMap<TKey, TValue> {
    add(key: TKey, value: TValue): void;

    get(key: TKey): Iterable<TValue>;
    size(key: TKey): number;

    keys(): Iterable<TKey>;

    has(key: TKey): boolean;
    has(key: TKey, value: TValue): boolean;

    delete(key: TKey): boolean;
    delete(key: TKey, value: TValue): boolean;
}