It's been done before, you know.
4 seconds sound clip from the The Roaring Twenties (1939) movie soundboard.
You can hear this line at 00:57:10 in the DVD version of the movie.
Quote context
[...]
- You can't spend your profits in the bottom of the ocean.
- Go on.
- What you mean is you want to double-cross Brown.
- It's been done before, you know.
- You could stand a little watching yourself.
- That sounds like a pretty good basis for a partnership.
[...]