SELECT "normalize"('abc', 'def');  -- run-time error
SELECT U&'\00E4\24D1c' IS NFC NORMALIZED AS test_nfc;
SELECT num, val,
    val IS NFC NORMALIZED AS NFC,
    val IS NFD NORMALIZED AS NFD,
    val IS NFKC NORMALIZED AS NFKC,
    val IS NFKD NORMALIZED AS NFKD
FROM
  (VALUES (1, U&'\00E4bc'),
          (2, U&'\0061\0308bc'),
          (3, U&'\00E4\24D1c'),
          (4, U&'\0061\0308\24D1c'),
          (5, '')) vals (num, val)
ORDER BY num;
SELECT is_normalized('abc', 'def');  -- run-time error