why does the sound of mp3 audio still use the old one, even though the sound has been replaced in mp3

[bobwatcherx]

I'm building a text to speech application. but when I retype a different sentence, why does the previous sound still sound? have I changed the voice with a new voice

my code

from flet import *
from gtts import gTTS
import os
import time

def main(page:Page):
	page.update()
	mytxt = TextField(label="my test")

	myaudio = Audio(
		src="https://fake.com/fake.mp3",
		autoplay=True
		)
	page.overlay.append(myaudio)


	def removeLates():
		path = os.path.join(os.getcwd(),"hello")
		for file in os.listdir(path):
			os.remove(os.path.join(path,file))
			print("YOU SUCCES DELETE OLD MUSIC !!!!")
			page.update()

	def showspeak(e):
		removeLates()
		time.sleep(1)
		tts = gTTS(text=mytxt.value,lang="en")
		tts.save("hello/hello.mp3")
		folder_path = "hello"
		extension = ".mp3"
		files = [file for file in os.listdir(folder_path) if file.endswith(extension)]
		if files:
			print("FILE Mp3 IS FOUND {} :".format(extension))
			for file in files:
				print(file)
				myaudio.src = file
				myaudio.play()
				print("ada file")
				page.update()
		else:
			print("NO FILE FOUND  {} IN HELLO FOLDER  {}.".format(extension, folder_path))

		page.update()

	page.add(
	Column([
	Text("Text TO speech app",size=30),
	mytxt,
	ElevatedButton("speak",
	on_click=showspeak,
	bgcolor="blue",
	color="white"
		)


	])
	)

flet.app(target=main,assets_dir="hello")

and create folder name is hello