minimal kivy and python code to use multiple widget using for loop via ScrollView

main.py

from kivy.app import App
from kivy.lang.builder import Builder
from kivy.uix.button import Button
from kivy.uix.boxlayout import BoxLayout
from kivy.properties import StringProperty


kv = """
<CWidget>:
    text: root.name
    background_color: "red" 
    size_hint: 1, None
    height: "60dp"

<SV>:
    BoxLayout:
        orientation: "vertical"
        Label:
            id: label
            text:'Scroll View'
            size_hint: 1, .3
            font_size: "25sp"
        ScrollView:
            do_scroll_y: True
            do_scroll_x: False
            BoxLayout:
                orientation: "vertical"
                size_hint_y: None
                height: self.minimum_height
                padding: 10
                BoxLayout:
                    orientation: "vertical"
                    id: wd
                    size_hint_y: None
                    height: self.minimum_height
"""

class CWidget(Button):
    name = StringProperty()

class SV(BoxLayout):
    def __init__(self, **kwargs):
        super().__init__(**kwargs)

        for i in range(20):
            self.ids.wd.add_widget(CWidget(
                name = str(i)
            ))

Builder.load_string(kv)

class Scroll(App):
    def build(self):
        return SV()
Scroll().run()