Common Lisp the Language, 2nd Edition
The function make-condition is the basic means for creating condition objects.
make-condition type &rest slot-initializations
Constructs a condition object of the given type using slot-initializations as a specification of the initial value of the slots. The newly created condition is returned.
The slot-initializations are alternating keyword/value pairs. For example:
(make-condition 'peg/hole-mismatch :peg-shape 'square :hole-shape 'round)