@@ -0,0 +1,373 @@
+def is_gregorian_leap_year(y):%0A    if (y %25 400) == 0:%0A        return True%0A    if (y %25 100) == 0:%0A        return False%0A    if (y %25 4) == 0:%0A        return True%0A    return False  # pragma: no cover%0A%0Adef days_in_month(year, month):%0A    if month == 2 and is_gregorian_leap_year(year):%0A        return 29%0A    return %5BNone, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31%5D%5Bmonth%5D%0A%0A

Create days_in_month fn in new internal module.