+(define-condition initarg-error (program-error)
+ ((class :reader initarg-error-class :initarg :class)
+ (initargs :reader initarg-error-initargs :initarg :initargs))
+ (:report (lambda (condition stream)
+ (format stream "~@<Invalid initialization argument~P:~2I~_~
+ ~<~{~S~^, ~}~@:>~I~_in call for class ~S.~:>"
+ (length (initarg-error-initargs condition))
+ (list (initarg-error-initargs condition))
+ (initarg-error-class condition)))))
+