TEST> (defclass foo ()
        ((bar :accessor bar :initarg :bar :initform 42)
         (baz :accessor baz :initarg :baz :initform :forty-two)))
#<STANDARD-CLASS FOO>

TEST> (defparameter *my-foo* (make-instance 'foo))
*MY-FOO*

TEST> (reinitialize-instance *my-foo* :baz #(when i was a young boy))
#<FOO {100F055A73}>

TEST> (bar *my-foo*)
42

TEST> (baz *my-foo*)
#(WHEN I WAS A YOUNG BOY)