stuff.ktn

def safeHead([a] -> a?):
    ->xs
    if (xs isEmpty):
        none
    else:
        xs head some

def find([a] (a -> Bool) -> a?):
    filter safeHead

def lookUp([a & b] a (a a -> Bool) -> b?):
    ->eq
    ->key              // 33
    {key eq} find      // 34
    {rest} liftOption

/*
stuff.ktn:33:5: note: t3332 is from here
stuff.ktn:34:5: type error: cannot solve infinite type constraint t3333 = t3333 t3332 t3339
stuff.ktn:34:5: note: this may be due to a mismatched number of arguments or results
stuff.ktn:34:6: note: t3333 is from here
stuff.ktn:34:14: note: t3339 is from here
(unknown): note: t3333 is from here
*/