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(2) I don't want to do that because it isn't like you can't
call bind() multiple times.  I would hate to get a Parameter
object with some suggested argument value, and then while I
had it have that value change because in another thread
someone called bind() on the Signature object again.

(3) Fair enough.  Changed to your suggestion in my version.

(4) OK, I see what you are getting at.  Changed in my
version.  I still wish there was a different exception that
I could use to flag that the binding didn't fail but that
the code couldn't figure out one without being destructive.

(5) Yep, that's a bug.  I have a test case for it now and
will work on fixing it.

(7) Fair enough.  Code changed and docstring updated.

I will work on fixing the bug I have that you reported.