Code review comment for lp:~jameinel/bzr/2.1-st-from-iterable

This is a small cleanup of Matt Nordhoff's update for 'from_sequence'. Basically, it changes the internals such that if an object isn't a simple sequence, we cast it to a tuple and then use that instead.

It means you can do "StaticTuple.from_sequence(generator)" which is what they had been doing in loggerhead. (using tuple(generator).)

I don't think we *need* this, but if it helps someone, I'm ok with it.