Leap year status differs from the official calendar for some years

[soroush]

The official calendar in Iran is an unknown combination of Birashk's method and 33-years algorithm, with some exceptions added. These exceptions are not handled in this library, so retrospectively speaking, there will be +-1 day shifts in JDN calculations for some years before 1375.

For future year numbers, there is no known calendar release or schedule ahead of the time, so we will have no means to calculate day shift for them.

[soroush]

Now that we have actually validated data from ut.ac.ir at https://github.com/soroush/calendars-data we can give it a shot...