[RFA] Fix PR python/17981

[Eli Zaretskii]

> From: Tom Tromey <tom@tromey.com>
> Cc: Tom Tromey <tom@tromey.com>,  gdb-patches@sourceware.org
> Date: Mon, 23 May 2016 13:06:51 -0600
> 
> Yao> Yes, it is correct, but it is better to explicitly document an empty
> Yao> sequence is returned if there are no breakpoints.
> 
> Here you go.

OK, thanks.