def setProperty(self, prop, *args, **kwargs):
        """
        Set the value of a property by sending an event on the root window.
        See the corresponding method for the required arguments. For example,
        for the property _NET_WM_STATE, look for :meth:`setWmState`
        """
        f = self.__setAttrs.get(prop)
        if not f:
            raise KeyError('Unknown writable property: %s' % prop)
        f(self, *args, **kwargs)