formatDuration function
Assumes the duration is in minutes
Implementation
String? formatDuration(Duration duration) {
if (duration.inMinutes == 0) return null;
final hours = duration.inHours;
final minutes = duration.inMinutes - (60 * hours);
return [
if (hours > 0) "$hours hour${hours > 1 ? 's' : ''}",
if (minutes > 0) "$minutes minute${minutes > 1 ? 's' : ''}",
].join(" ");
}