It is easy, when declaring a class you just use the “with” keyword as often as you want
class CollegeStudent extends Student with Worker with Underpaid with Young
the order of the traits can be important if a trait is changing the behavior of the class, it all depends on traits you are using.
Also if you don’t want to have a class which always uses the same traits you can use them later:
class CollegeStudent extends Student
new CollegeStudent with Worker with Underpaid with NotSoYoungAnymore