toLocal method
Returns a Period with the start and end in local time.
If this
isLocal, it will be returned.
If eiher start or end is not in local time, a new Period will be
created with the start and end converted to local time.
Implementation
Period toLocal() {
if (isLocal ?? false) return this;
return Period(
start: start.toLocal(),
end: end.toLocal(),
);
}