export declare class Bag<K, V> {
    readonly name: string;
    readonly map: Map<K, V>;
    constructor(name: string);
    add(name: K, value: V): void;
    has_own(name: K): boolean;
    has(name: K): boolean;
    try_lookup(name: K): NonNullable<V> | null;
    lookup(name: K): NonNullable<V>;
}