John Flanagan said this quote

“ Halt glared at his friend as the whistling continued.'I had hoped that your new sense of responsibly would put an end to that painful shrieking noise you make between your lips' he said.Crowley smiled. It was a beautiful day and he was feeling at peace with the world. And that meant he was more than ready to tease Halt 'It's a jaunty song''What's jaunty about it?' Halt asked, grim faced. Crowley made an uncertain gesture as he sought for an answer to that question.'I suppose it's the subject matter' he said eventually. 'It's a very cheerful song. Would you like me to sing it for you?''N-' Halt began but he was too late, as Crowley began to sing. He had a pleasant tenor voice, in fact, and his rendering of the song was quite good. But to Halt it was as attractive as a rusty barn door squeaking.'A blacksmith from Palladio, he met a lovely lady-o''Whoa! Whoa!' Halt said 'He met a lovely lady-o?' Halt repeated sarcastically 'What in the name of all that's holy is a lady-o?''It's a lady' Crowley told him patiently.'Then why not sing 'he met a lovely lady'?' Halt wanted to know.Crowley frowned as if the answer was blatantly obvious.Because he's from Palladio, as the song says. It's a city on the continent, in the southern part of Toscana.''And people there have lady-o's, instead of ladies?' Asked Halt'No. They have ladies, like everyone else. But 'lady' doesn't rhyme with Palladio, does it? I could hardly sing, 'A blacksmith from Palladio, he met his lovely lady', could I?''It would make more sense if you did' Halt insisted 'But it wouldn't rhyme' Crowley told him.'Would that be so bad?''Yes! A song has to rhyme or it isn't a proper song. It has to be lady-o. It's called poetic license.''It's poetic license to make up a word that doesn't exist and which, by the way, sound extremely silly?' Halt asked.Crowley shook his head 'No. It's poetic license to make sure that the two lines rhyme with each other'Halt thought for a few seconds, his eyes knitted close together. Then inspiration struck him.'Well then couldn't you sing 'A blacksmith from Palladio, he met a lovely lady, so...'?''So what?' Crowley challengedHalt made and uncertain gesture with his hands as he sought more inspiration. Then he replied. 'He met a lovely lady, so...he asked her for her hand and gave her a leg of lamb.''A leg of lamb? Why would she want a leg of lamb?' Crowley demanded Halt shrugged 'Maybe she was hungry ”