[web2py] IS_EMPTY_OR with list instead of one

[Carlos]

Hi,

Shouldn't IS_EMPTY_OR accept a list instead of only one alternative
validator as arg 0?.

For example in the case where an email field can be either empty or
unique, in which case we would need something like the following:

IS_EMPTY_OR([ IS_EMAIL(), IS_NOT_IN_DB(db, db.table.email) ])
('em...@email.email')

What do you think?.

   Carlos