Holidays dates for planned_date

We have a case where the shipments must be delivered to customer at some specific date and the carrier ask for the package the day before. As the company don’t work on sundays and saturdays the shipments which customer wants on monday have to be shipping_date on friday.
This is not problem with datetime.isoweekday().

We found missing some holiday module where companies can define the holiday dates. Or better, the dates can be fuzzy imported (and aproved latter) on fiscal year creation.

This can be also be usefull to not set planned_date on those days.

Any other find this a interesting feature? Any suggestions or edge cases?

Indeed this could be implemented in a module sale_shipping_day similar to stock_supply_day but that applies to compute_shipping_date and with the weekdays defined by default on the company (and optionally on the product).

I think it will be better to just use this holidays module without importing in the database the days. But if the dates from the module must be modified, then the user could create an override of the dates by creating a record for the year (I would not link that to the fiscal year) which will be prefilled by the existing holidays.
The holidays should be defined per company (but the design should allow to extend that to add for example the warehouse). The user will choose a list of countries and provinces/states.