Define a SCHEME function, unzip, which takes a list of pairs ((a1 .b1 ). . .(an .bn )) and returns a pair consisting of the two lists (a1 . . . an ) and (b1 . . . bn ). Note that these functions are not exactly inverses of each other, since zip takes its lists as a two arguments, while unzip produces a pair of lists. Finally, it is wise to realize how SCHEME prints out a pair of lists. Consider the statement (cons (list 1 2) (list 3 4)) which denotes a pair of lists. It prints as ((1 2) 3 4).