After years of efforts, countries decided where exactly the Prime Meridian and the equator would cross each other.

Those two checks for isValid() followed by null-check are out of order. The call to isValid() is done on a null object. This patch solves the issue: diff --git a ...

Currently, the model classes do not provide a copyWith function that safely checks for null values before assignment. It would be useful to add a copyWith implementation that updates only the provided ...