def add_widget(self, widget, index=0):
        if self._container or not widget:
            return Exception('Splitter accepts only one Child')
        self._container = widget
        sz_frm = self.sizable_from[0]
        if sz_frm in ('l', 'r'):
            widget.size_hint_x = 1
        else:
            widget.size_hint_y = 1

        index = 0
        if ('r', 'b') in sz_frm:
            index = 1
        super(Splitter, self).add_widget(widget, index)
        self.on_sizable_from(self, self.sizable_from)
dataset/ETHPy150Open kivy/kivy/kivy/uix/splitter.py/Splitter.add_widget/swapped operands of `in`