Module dates 

Calendar arithmetic for the pickers (proleptic Gregorian, no clock).

Constants

MONTHS

WEEKDAYS_SHORT

Functions

add_days

The day n days after (y, m, d).

days_in_month

format

is_leap

label

Oct 7, 2026 (the en medium date; natives format in the surface locale from the ISO value).

parse

yyyy-mm-dd → (y, m, d).

shift_month

The month after/before.

weekday

0 = Sunday … 6 = Saturday (Sakamoto).