My nanny. She's the one who sings that ridiculous song.
5 seconds sound clip from the Mary Poppins movie soundboard.
You can hear this line at 02:09:49 in the Blu-ray version of the movie.
Quote context
[...]
- I might pop through a chalk pavement picture and go for an outing in the country.
- Or I might seize a horse off a merry-go-round and win the Derby!
- Poppins?
- My nanny. She's the one who sings that ridiculous song.
- A spoonful of sugar makes the medicine go down.
- Father? Father! Father, come down!
[...]