Hi,

While testing Tkinter.Canvas I've found several minor bugs that I would
prefer to see fixed. Many of them change the current Canvas api a bit,
but for better. For example, the methods "focus", "gettags", "icursor",
"index", "insert", "move" (and some others) accept arbitrary amount of
arguments, but all these tcl subcommands have a fixed amount of
arguments they accept, so I consider it is better to make this clear on
Tkinter too.

I've also found a problem in Misc._configure which is also fixed by the
attached patch. The problem is that when cnf is a string, the call
"self.tk.split(self.tk.call(_flatten((self._w, cmd, '-'+cnf))))" may
still result in an empty string causing the following statement to fail
"return (x[0][1:],) + x[1:]".

One thing that left me curious was the comment "# XXX Should use
_flatten on args" in Canvas.coords. I've tried understanding why it
should use _flatten there, but couldn't figure it out. This is a very
old comment, so maybe it is no longer true ?