RadioButtonGroup not working on generic jupyter notebook

Panel
1

I was trying to replicate RadioButtonGroup — Panel v1.2.1 on my own jupyter notebook. But however I tried, by clicking “Chemistry” or “Physics”, the output of radio_group.value is always “Biology”. Any hints on this? I used exactly the same code as the example

import panel as pn  # GUI
pn.extension()
---
radio_group = pn.widgets.RadioButtonGroup(
    name='Radio Button Group', options=['Biology', 'Chemistry', 'Physics'], button_type='success')

radio_group
---
radio_group.value
2

OK, it works after I restarted Jupyter notebook. I guess it is some sort of caching issue.