[web2py] 2 field unique validator

Not sure if this is the problem but the book always shows multiple validators enclosed in square brackets [].

[web2py] 2 field unique validator

I know this question has been asked and answered before, but I am having errors in implementation and I feel like it's something really silly. If anyone can point anything obvious out that I am missing, please let me know. Basically I am trying to implement so that two rows can not have the same co