cnf argument for tkinter widgets
<p>So, I'm digging through the code <a href="http://svn.python.org/projects/python/branches/pep-0384/Lib/tkinter/__init__.py" rel="noreferrer">here</a> and in every class (almost) I see an argument <code>cnf={}</code> to the constructor, but unless I've missed it, it is not explicitly stated what cnf is / expected to contain. Can anyone clear this up? At first I thought it was for the keywords passed to tkinter widgets, but kw is appropriately for that. So, I'm confused about what role <code>cnf={}</code> is playing.. as well as the <code>extra=()</code> argument(s).</p>