chkAppend :: [a] -> [a] -> [a]
-- Checks for the second arguemnt being empty
-- Used in situations where that situation is common
chkAppend xs ys
  | null ys   = xs
  | otherwise = xs ++ ys
chkAppend :: [a] -> [a] -> [a]
chkAppend xs ys
  | null ys   = xs
  | otherwise = xs ++ ys
chkAppend xs ys
  | null ys   = xs
  | otherwise = xs ++ ys