'Test the widget\'s state.
If callback is not specified, returns True if the widget state
matches statespec and False otherwise. If callback is specified,
then it will be invoked with *args, **kw if the widget state
matches statespec. statespec is expected to be a sequence.'

def instate(self, statespec, callback=None, *args, **kw):

    ret = self.tk.call(self._w, 'instate', '    '.join(statespec))
    if (ret and callback):
        return callback(*args, **kw)
    return bool(ret)
