Must be somebody there, because somebody must have said, 'Nobody'.
8 seconds sound clip from the The Many Adventures of Winnie the Pooh movie soundboard.
You can hear this line at 00:14:30 in the Blu-ray version of the movie.
Quote context
[...]
- Oh, my. Oh, my goodness gracious!
- Is anybody at home? What I said was, 'Is anybody at home?'
- No!
- Bother! Isn't there anybody here at all?
- Nobody.
- Must be somebody there, because somebody must have said, 'Nobody'.
- No.
- Isn't that the Rabbit's voice?
- I don't think so. It isn't meant to be.
[...]