kivy listproperty not updated in label after change

Question

I have two list email2 and email3 as ListProperty(rebind=True) but when email2 and email3 list change in python code , same is not reflected in label in kv file .

    ScrollView:
        do_scroll_x: False
        do_scroll_y: True
        pos_hint:{"x":0.3, "y": 0.1}
        size_hint:0.6,0.7


        GridLayout:
            cols: 1
            orientation: "vertical"
            size_hint_y: None
            height: self.minimum_height
            on_parent:
                for i in range(len(root.email2)): txt = root.email3[i]; clr= utils.get_color_from_hex(root.email2[i]); self.add_widget(Label( text = txt,font_size=16, pos=self.pos,size_hint_y= None,color=clr))