def METHOD_NAME(cls,win):
    if len(cls.registered_windows()) > 0:
        # visit will always have one valid window
        # when more than one Window instance is registered
        # we need to add an addtional window.
        visit.AddWindow()
    # get active window id from global atts
    gatts = visit.GetGlobalAttributes()
    rid = gatts.windows[gatts.activeWindow]
    visit.SetActiveWindow(rid)
    cls.__windows[rid] = win
    return rid