Pythonic Abstract Base Class / Interface

[Tom Evans]

Tom Evans wrote:
> So, as I see it I could:
> a) create a base class with stubs for all the interface and derive from that.
> b) create an empty base class and derive from that.
> c) just make the concrete classes directly with no inheritance commonality.

Thanks for all the responses.  It would appear that there is no 
One True Way.  What I've learnt:

I was originally just whipping something up, not sure what the final 
solution was going to look like.  In that case, it would appear (c) 
was the way to go.

If I wanted to document exactly what the interface should be once I'm sure 
it's the right solution, (a) with document strings and raising 
NotImplementedError might be a good place to put that documentation.
  (btw, thanks -- I didn't know about NotImplementedError before)

On the face of it, (b) appears to be the loser.  But it would give me 
isinstance if I wanted it, and might allow me to convert more easily 
from (a) to (c) in the future.  

thanks to all,
Tom