Kivy кликер

from kivy.app import App
from kivy.uix.button import Button
from kivy.uix.boxlayout import BoxLayout
from kivy.uix.label import Label
from time import sleep
count = 0
class RegApp(App):
 
    def timer(self,instance):
            global count
            while count < 99:
                count += 1
                self.formula += 1
                self.lbl.text = "0."
                self.lbl.text += str(self.formula)
                sleep(0.01)
                
    def build(self):
        self.formula = 0
        bl = BoxLayout(orientation = "vertical")
        self.lbl = Label(text = "0")
        self.btn = Button(text = "СТАРТ" , on_press = self.timer)
        bl.add_widget(self.lbl)
        bl.add_widget(self.btn)
        return bl
if __name__ == "__main__":
    RegApp().run()

from kivy.app import App
from kivy.clock import Clock
from kivy.uix.button import Button
from kivy.uix.boxlayout import BoxLayout
from kivy.uix.label import Label
 
 
 
class RegApp(App):
 
    def reset_label(self, *args):
        if self.formula < 99:
            self.formula += 1
            self.lbl.text = f"0.{str(self.formula)}"
            Clock.schedule_once(self.reset_label, 0.01)
        else:
            return
 
 
    def timer(self, instance):
        self.formula = 0
        self.reset_label()
 
 
    def build(self):
        self.formula = 0
        bl = BoxLayout(orientation="vertical")
        self.lbl = Label(text="0")
        self.btn = Button(text="СТАРТ", on_press=self.timer)
        bl.add_widget(self.lbl)
        bl.add_widget(self.btn)
        return bl
 
 
if __name__ == "__main__":
    RegApp().run()