4. 18 marks] Consider the following Scheme code:
idefine (eval vi v2)
(cora
(and (> vl 0) (> V2 C)) (+ vl v2) 2)1
[(or 1> v! 0) (> v2 O)) (max v: v2)
[else 'regative-valcos:))
a) [2 marks Write the contract for eval.
b) [2 marks) Write a purpose for eval.
c) 14 marks Write 4 separate, distinct tests for eval.
(check-expect
(check-expect
(check-expect
(check-expoco
