How can I push a mutable pair onto a stack such that i'm only creating one stack. I have some code that works but creates lists within lists within lists.... Here is what I believe should work but throws an error.

(define func (arg1 arg2 arg3) // Where arg3 is an empty list
    (mappend (mcons arg1 arg2) arg3))

The above code complains and says: "mcar: expects argument of type ; given ... Can anyone show me how I can get a result that looks like so,: (list (arg1 arg2) (arg# arg#) ...)