[PD] How to remove duplicate elements from a list???

Hello,

Is there a way to remove duplicate elements for a list? I can figure out how to do it in code, but trying to figure out a way to do this with lists just makes my head hurt.

I want to do Boulez-style pitch-set multiplication with lists, and typically after such an operation, duplicate elements are removed.

I already made an abstraction called "Schoenberg" which I will post shortly, which allows one to do basic serial operations using lists (ie. transposition, retrograde, inversion, and rotation, all using one simple abstraction). I know that serialism has been out of style for 40 years, but nevertheless those methods make a lot of sense to have available, if one is making nontonal generative/aleatoric music.

~David