export declare function getOrCreate<TKey, TValue>(input: Map<TKey, TValue>, key: TKey, buildDefaultValue: () => TValue): TValue;
export declare function areMapsEqual<K, V>(a: ReadonlyMap<K, V>, b: ReadonlyMap<K, V>): boolean;
export declare function mustGet<K, V>(map: ReadonlyMap<K, V>, key: K): V;