from YAHT Exercise 4.9 Write a function elements which returns the elements in a BinaryTree in a bottom-up, left-to-right manner (i.e., the ���rst element returned in the left-most leaf, followed by its parent���s value, followed by the other child���s value, and so on). The re- sult type should be a normal Haskell list. here's the data type BinaryTree data BinaryTree a = Leaf a | Branch (BinaryTree a) a (BinaryTree a) Here's my first attempt nodeCount :: BinaryTree a -> [b] nodeCount = map putStrLn (show a) a is out scope. I started looking at what types putStrLn and map are. First thing that occurs to me is that I can't use map unless I pass it a list. I'm not allow to use fold yet, that's the next assignment. Any clues on how to proceed?