Is there any possible way to set the non-working days for "Process Calendar" at once?

Hello?

Is there a way to set the working days and non-working days of the process calendar at once

without selecting them one by one in [Appian Designer -> objects -> Process calendar]?

I have found out some plug-ins at the AppMarket.

   1. Business Calendar Management

   https://community.appian.com/b/appmarket/posts/business-calendar-management 

   2. Calendar IO

   https://community.appian.com/b/appmarket/posts/calendar-io

Both are mentioning about "uisng database".

I tired to find the table for the calendar in the database but was not succesful.

(Save calendar function seems to be deprecated. Which is the function that I need most.)

How do Appian Developers usually manage business calendar?
Do you create and use a separate calendar other than the process calendar provided by appian?
Or is there an easier and more convenient way to set the appian process calendar?

Functional support for setting up a business calendar is a very basic essential function, is there really no such supporting function in Appian?

Thank you