You made that up.
4 seconds sound clip from the Mary Poppins movie soundboard.
You can hear this line at 01:14:03 in the Blu-ray version of the movie.
Quote context
[...]
- I must say, you're a sight, the lot of you!
- Speaking of sight, it reminds me of me brother.
- He's got a nice cushy job in a watch factory.
- In a watch factory? What does he do?
- He stands about all day and makes faces!
- Well, it's the most disgraceful sight I've ever seen, or my name isn't Mary Poppins.
- Speaking of names, I know a man with a wooden leg named Smith. What's the name of his other leg?
- Wasn't that funny? What's the name of his other...
[...]