randomString function
Implementation
String randomString(int length) {
var r = Random();
const _chars = 'AaBbCcDdEeFfGgHhIiJjKkLlMmNnOoPpQqRrSsTtUuVvWwXxYyZz';
var stringWithoutNumber =
List.generate(length, (index) => _chars[r.nextInt(_chars.length)]).join();
return stringWithoutNumber;
}