I have these small lines:

Timestamp timestamp = document.get("timestamp");
DateTime time = timestamp.toDate();
time.add(const Duration(hours: 3));
print(time);

And before adding hours this is time:

And after adding 3 hours its value is the same:

What can it be caused by?

>Solution :

If you check the documentation of the add method you will see that it’s not a setter, rather it returns a new DateTime so you need it to assign to a new value.

var threeHoursFromNow = time.add(const Duration(hours:3));