Double Flat Signs

I'm learning Chopin Nocturne Op 9 No 2 and on measure 29 and then again on measure 32, one of the B flats has 2 flat signs next to it. If you don't have the sheet music and/or are unfamiliar, if you watch the youtube video below, it's at about the 3 minute mark where you can see this section of the music (1st measure of the 2nd line is measure 29).

https://www.youtube.com/watch?v=YGRO05WcNDk

Is this a typo? Or does it mean something I just have never encountered before?

The first note is a C flat. So is the following note supposed to be B flat and then 2 more B flats?

Help?

Its very simple, there just double flats. Two semi-tones down, ignoring the key signiture. So measure 29 and 32 you will play A's.

Good luck.

I'm sorry, I still don't understand. I edited my initial post because this cold is screwing with my ability to speak or write clearly and I confused myself reading what I wrote. haha not to mention I forgot that C flat and B natural were the same note.

Anyway, so I play C flat, B flat and then instead of B flat again, I play 2 semitones down from it so A flat? And do I then go back to B flat and then 2 A flats, etc? If that's the case, why the double flat signs at all and not just write A flat?? haha

Thanks again for helping me clarify this.

From the start of that bar line, it will be: C flat (B), B flat, then A.

I get it now I think. I also watched a couple of youtube videos where I could see their hands during that section and confirmed I do understand what you're saying.

I probably shouldn't be trying to grasp new concepts, simple ones or not, with a cold. lol

Anyway, thanks!

Oh I see your edit! Thanks! But can you explain the point of using the double flats? Why not just put an A there with a natural sign next to it? I'm sure there's an explanation for it but seems unnecessarily confusing to me.

It's used to stop the music becoming to cluttered. Let me TRY and explain this, it's quite hard :p, but say your in an A flat key, and you have to play, D flat, D Nautral, D flat, D nautral and so forth. The music sheet will be jammed packed with LOADS of diffrent notes and symbols. So to make it alot less cluttered, you would write the D nautral as a E double flat. That way you only write one double flat symbol on the E.

Got it, thanks! I appreciate your help.