;;; library required

(define l '(a (1 2 (3 4) 5) b))
(memv 'a l) 
(memv '(1 2 (3 4) 5) l) 
(member '(1 2 (3 4) 5) l)
(define k '((a 1) (b 2) ((((a))) 3)))
(assq 'a k)
(assq '(((a))) k)
(assoc '(((a))) k)