nubOrd "this is a test" == "this ae" nubOrd (take 4 ("this" ++ undefined)) == "this" \xs -> nubOrd xs == nub xs
nubSort "this is a test" == " aehist" \xs -> nubSort xs == nub (sort xs)
drop1 "" == "" drop1 "test" == "est" \xs -> drop 1 xs == drop1 xs
dropEnd1 "" == "" dropEnd1 "test" == "tes" \xs -> dropEnd 1 xs == dropEnd1 xs