'Move window to a specified screen, or the current screen.'

def toscreen(self, index=None):

    if (index is None):
        screen = self.qtile.currentScreen
    else:
        try:
            screen = self.qtile.screens[index]
        except IndexError:
            raise command.CommandError(('No    such    screen:    %d' % index))
    self.togroup(screen.group.name)
