wrong = VALID +'a'
self.assertRaises(WrongUUID4, is_uuid4, wrong)
# test UUID4 format validation
self.assertRaises(WrongUUID4, is_uuid4, VALID.replace('4', '3'))
wrong = VALID +'a'
self.assertRaises(WrongUUID4, is_uuid4, wrong)
# test UUID4 format validation
self.assertRaises(WrongUUID4, is_uuid4, VALID.replace('4', '3'))