I am stuck on an exercise in a haskell book (the craft of functional programming) chapter 7 exercise 7.18 I have to write a function to check does one list occur as a subsequence of another, i am having real difficulty trying to do this. I have a method which will tell me if one character occurs in the list but it won't work for a list of characters. the function should look like isSubsequence :: [chars] -> [chars] -> boolean