It would appear to be a bit out of date

readme.org

@@ -11,15 +11,17 @@ The pre-defined procedures ~min~ and ~max~ each take two arguments and return th
 
 Implement ~deepSum~, where given an instance of ~Nested~, defined below, an arbitrarily nested list of numbers, ~deepSum~ the sum of all the numbers. That is, your input list may have sublists, which may themselves have sublists and so on.
 #+BEGIN_SRC haskell
-data Nested a = Value a | List [NestedList a]
+data NestedList a = Value a | List [NestedList a]
 #+END_SRC
 
 Which can be instantiated as follows:
 #+BEGIN_SRC haskell
+-- while x is of the type NestedList, we never directly instantiate a NestedList
+-- Instead, instantiate the types Value or List
 x = (List [Value 3, List [Value 2, Value 3], Value 4])
 #+END_SRC
 
-Implement deepsum on an instance of Nested instead of arbitrarily nested lists.
+Implement ~deepsum~ on an instance of ~NestedList~ instead of arbitrarily nested lists.
       a. Haskell has stricter type requirements than Scheme did. What would be true of nested arrays in Haskell?
       b. Implement the function
 * Question 2 - Prime numbers