How to display the contents of the second class in the window when the button in the first class (kivy) is clicked?

Question

IT education

How to display the contents of the second class in the window when the button in the first class is clicked?
Here is the code:

from kivy.app import App
from kivy.uix.label import Label
from kivy.uix.widget import Widget
from kivy.uix.button import Button
class Wirtuling(Widget):
    def btn_clk_d(self):
        self.nu.text="OK"
    def btn_clk_f(self):
       return Widgets()
class Widgets(Widget):
    def __init__(self):
        super(Widgets, self).__init__()
    def btn_clk_b(self):
       return Wirtuling()
class SimpleKivy(App):
    def build(self):
        return Widgets()
myApp = SimpleKivy()
myApp.run()

And here is the kv file:

<Widgets>:
    Button:
        size: 170,75
        pos: 100,0
        text: "sb"
        color: 1,0,0,1
        font_size: 40
        on_press: root.btn_clk_b()
<Wirtuling>:
    nu:nu_c
    Button:
        size: 170,75
        pos: 0,0
        text: "play"
        color: 0,1,0,1
        font_size: 40
        on_press: root.btn_clk_d()
    Button:
        size: 170,75
        pos: 100,0
        text: "naz"
        color: 1,0,0,1
        font_size: 40
        on_press: root.btn_clk_f()
    TextInput:
        id: nu_c
        size: 300,300
        pos: 300,0
        text: ""
        color: 1,0,0,1
        font_size: 40
    TextInput:
        id: nu_d
        size: 300,300
        pos: 300,300
        text: ""
        color: 1,0,0,1
        font_size: 40

Tell me what's wrong? Thanks in advance.

Answer 1

matlab and python.

Answer 2

R or Wolfram .

Answer 3

C++ obviously