I have code in python (Test.py)

import flet
from flet_timer.flet_timer import Timer

def AppScreen(Page):
    Page.theme_mode = flet.ThemeMode.LIGHT
    Page.window_width = 1100

    TimerText = flet.Text(value='0', size=25, color="#28609f")
    def TimerPlus():
        TimerText.value=int(TimerText.value)+1
        Page.update()

    Page.add(
        flet.Row(
            controls=[TimerText, Timer(name="ShiftCount", interval_s=1, callback=TimerPlus)],
            alignment=flet.MainAxisAlignment.CENTER
        )
    )


        
flet.app(target=AppScreen)

I run flet publish Test.py and then python3 -m http.server –directory dist

When I go to http://localhost:8000 I get error

Unhandled Promise Rejection: PythonError: Traceback (most recent call last):
  File "/lib/python311.zip/_pyodide/_base.py", line 571, in eval_code_async
    await CodeRunner(
  File "/lib/python311.zip/_pyodide/_base.py", line 39...
(anonymous function) - python-worker.js:42

How to fix it?