*** INSERT Input: \f -> f ((<)::Char->Char->Bool) '1' "" == "1" && (f (<) '2' "" == "2") && (f (<) '3' "" == "3") && (f (<) '1' "2" == "12") && (f (<) '2' "1" == "12") && (f (<) '2' "3 4" == "23 4")