wxTaskBarIcon used in demo example from wxPython2.8-win32-docs-demos

Hi,

I don't understand from where come "FRAME" in "self.frame = frame"
I can't find to be used "frame" like argument.
Class DemoTaskBarIcon is used this way "self.tbicon =
DemoTaskBarIcon(self)"

class DemoTaskBarIcon(wx.TaskBarIcon):
    TBMENU_RESTORE = wx.NewId()
    TBMENU_CLOSE = wx.NewId()
    TBMENU_CHANGE = wx.NewId()
    TBMENU_REMOVE = wx.NewId()
    
    def __init__(self, frame):
        wx.TaskBarIcon.__init__(self)
        self.frame = frame

Thanks in advance from your answer!