[web2py] adding fields to SQLFORM.factory

[b0j3]

Hi!

I'd like to add new fields to SQLFORM.factory, but I don't know in
advance how many fields are there and their names.
So I'd like to create something as tuple with field names and then use
for command to cycle through the tuple and create Fields to add to
SQLFORM.factory.

Can something like that be done and how?
All examples I see are with already created fields.

Thanks,

Boštjan