/**
 * Adds the given number of years to the given date and returns a new Date object.
 *
 * @deprecated Use {@link shiftYears} instead.
 */
export declare function addYears(years: number, date?: Date): Date;
/**
 * Shifts the given date by a specified number of years and returns a new Date object.
 *
 * Can take both positive and negative values for years.
 *
 * @param {number} years - The number of years to add to the date.
 * @param {Date} [date=new Date()] - The date to add the years to. Defaults to the current date.
 * @returns {Date} - A new Date object with the given number of years added.
 */
export declare function shiftYears(years: number, date?: Date | string | number): Date;