-- | Check if argument is one of @\'a\', \'e\', \'i\', \'o\', \'u\'@.
isLowerVowel :: (FromAscii a, Eq a) => a -> Bool
isLowerVowel = is 97 <||> is 101 <||> is 105  <||> is 111 <||> is 117
isLowerVowel :: (FromAscii a, Eq a) => a -> Bool
isLowerVowel = is 97 <||> is 101 <||> is 105  <||> is 111 <||> is 117
isLowerVowel = is 97 <||> is 101 <||> is 105  <||> is 111 <||> is 117