(defgeneric dishes (obj)
(:method-combination progn)
;;;^^^^ option is available at http://www.lispworks.com/documentation/lw70/CLHS/Body/m_defgen.htm#defgeneric
(:method progn (obj)
;;;^^^ а эта опция где описана.
(format t "- clean and dry.~&"))
(:method progn ((obj person))
(format t "- bring a person's dishes~&"))
(:method progn ((obj child))
(format t "- bring the baby dishes~&")))