export interface InnerMap<V> {
    [key: string]: V;
}
export declare type ToKeyFunction<V> = (value: V) => string;
export declare class SetMultimap<K, V> {
    private readonly keyToKey;
    private readonly valueToKey;
    private backing;
    constructor(keyToKey: ToKeyFunction<K>, valueToKey: ToKeyFunction<V>);
    put(key: K, value: V): void;
    putAll(key: K, values: ReadonlyArray<V>): void;
    get(key: K): ReadonlyArray<V>;
    delete(key: K): boolean;
    filter(key: K, predicate: (value: V) => boolean): void;
    containsKey(key: K): boolean;
}