8. (15) (a) What is the type of the following unknown9 function? Give the most general type and include any required class constraints. The function length returns type Int.

> unknown9 [] = [] > unknown9 (x:xs) = (a , x) : b > where > a = length $ x : takeWhile (==x) xs > b = unknown9 (dropWhile (==x) xs)

(b) Give a description of what the unknown9 function in part (a) does. Describe what it does, not how it works.

(c) Give a non-trivial test case for the unknown8 function in part (a) and show the expected results.