'Pull a group to a specified screen.
Parameters
screen :
Screen offset. If not specified, we assume the current screen.
Examples
Pull group to the current screen::
toscreen()
Pull group to screen 0::
toscreen(0)'

def cmd_toscreen(self, screen=None):

    if (screen is None):
        screen = self.qtile.currentScreen
    else:
        screen = self.qtile.screens[screen]
    screen.setGroup(self)
