Is there a way to count unique values while grouping in Altair Monarch?
I'm working with a dataset that contains credit and debit cards information. I've done some analysis but now I would like to group the following way:

group by: BANK, TYPE, INDUSTRY
sum: AMOUNT, TRANS
count unique values: ID, PLASTIC
There is not a count unique option while grouping so I would appreciate and advice as to how to handle this operation in the future.
