formatDateTime function
Implementation
String formatDateTime(DateTime dt) {
final hh = dt.hour.toString().padLeft(2, '0');
final mm = dt.minute.toString().padLeft(2, '0');
return '${dt.year}-${dt.month.toString().padLeft(2, '0')}-${dt.day.toString().padLeft(2, '0')} $hh:$mm';
}