:-use_module(library(auth)). writeln(T) :- writeq(T), nl. test1a :- auth:adduser(user1,pass1), writeln('OK'). test1a :- writeln('OOPS already exists'). test1b :- auth:deluser(user1), writeln('OK'). test1b :- writeln('OOPS not exists'). test2a :- auth:adduser(user2,pass1), writeln('OK'). test2a :- writeln('OOPS already exists'). test2b :- auth:deluser(user2), writeln('OK'). test2b :- writeln('OOPS not exists'). test99 :- auth:save, auth:listusers(L), writeln(L), writeln('OK').