Searching for a special prolog predicate

Searching for a special prolog predicate

pI need a simple Prolog predicate like:/p
pmake_list_elements_unique([1,1,1,2,2,3], X) with X = [1,2,3]./p pBefore
starting to write it on my own, I want to search for a built-in predicate.
I can't suggest that Prolog hasn't such a predicate./p pDo you know it??/p
pThanx for your help!!/p