Code review comment for lp:~garyvdm/bzr/register_lazy_decorated

thanks for working on this.

some minor notes:
I'd prefer if this doesn't use exception handling to decide
what the previous command is, rather check it:

- try:
+ if key in self:
             previous = self.get(key)
- except KeyError:
+ else:
             previous = _builtin_commands().get(key

There are some lines longer than 79 chars:
commands.py line 116 and 138.
There are also a bunch of blank lines with whitespace, which can be cleaned up.

other than that it looks fine to me.
(I haven't actually tried out this functionality yet, but I'd like to soon.)
bb:tweak