def maximize(self):
        "Grow the currently focused client to the max size"
        # if we have 1 or 2 panes or main pane is focused
        if len(self.clients) < 3 or self.focused == 0:
            self._maximize_main()
        # secondary is focused
        else:
            self._maximize_secondary()
        self.group.layout_all()
Grow the currently focused client to the max size
libqtile/layout/xmonad.py