- (let ((combin (getf ,all-keys :method-combination '.shes-not-there.)))
- (unless (eq combin '.shes-not-there.)
- (setf (getf ,all-keys :method-combination)
- (find-method-combination (class-prototype ,gf-class)
- (car combin)
- (cdr combin)))))
+ (let ((combin (getf ,all-keys :method-combination)))
+ (etypecase combin
+ (cons
+ (setf (getf ,all-keys :method-combination)
+ (find-method-combination (class-prototype ,gf-class)
+ (car combin)
+ (cdr combin))))
+ ((or null method-combination))))