/**
 * Helper to mimic Python's defaultdict plus-equal operator.
 */
export declare const defaultdictPlusEqual: <T>(mapping: Map<T, number>, key: T, value: number) => void;
/**
 * Helper to mimic python's lstrip function
 */
export declare const lstrip: (str: string, chars: string) => string;
/**
 * Helper method to mimic python's partition function
 */
export declare const partition: (str: string, sep: string) => [string, string, string];
/**
 * Helper map to work with array keys, by stringifying them before use.
 * Otherwise, JS will use the default object equality check, which will
 * not work for arrays.
 */
export declare class ArrayKeysMap<K, T> {
    private _map;
    constructor(entries?: [K, T][]);
    [Symbol.iterator](): IterableIterator<[K, T]>;
    private encodeKey;
    get(key: K): T;
    set(key: K, val: T): void;
    has(key: K): boolean;
    delete(key: K): void;
    pop(key: K): T;
    entries(): [K, T][];
}