/// export function sortProvince(arr: ProvinceCityChina.Level[], level?: number): ProvinceCityChina.Level[]; export function findCityChild(arr: ProvinceCityChina.Level[], code: string, level?: number): ProvinceCityChina.City[]; export function findAreaChild(arr: ProvinceCityChina.Level[], code: string, level?: number): ProvinceCityChina.Area[];