/**
 * 识别股票代码添加市场后缀
 *
 * @param {string} stock 股票代码
 * @returns {string} 带有市场后缀的股票代码
 * @example
 *
 * appendStockSuffix('600570')
 * // => '600570.SS'
 */
export declare function appendStockSuffix(stock: string): string;