/**
 * Parses `CronLast` into a string.
 *
 * @category Parsers
 * @example
 * ```typescript
 * parseCronLast("L"); // "L"
 * parseCronLast("💩"); // undefined
 * ```
 * @param source `CronLast` to be parsed.
 * @returns A string or `undefined` if invalid.
 */
export declare const parseCronLast: (source: string) => "L" | undefined;