Can't change page in multipage streamlit app

Using Streamlit
1

Hi, I am building a multipage app, but cannot change the page when I run it locally. I currently have the different pages set-up as radio options in the sidebar. When I click on a different page/radio button, it jumps back to the first page again. There’s no error message - it just pretends as if I never tried to change the page.

I’m using a Python venv in PyCharm.
streamlit: 0.85.1
python: 3.8.2
macOS: Big Sur 11.4

The code for my app.py file looks like this…

import streamlit as st
from multiapp import MultiApp

# FIRST PAGE
def something():
    st.title('SOMETHING')

# SECOND PAGE
def something_else():
    st.title('Something Else')

# CREATE PAGES IN APP
app = MultiApp()
app.add_app("First Page", something)
app.add_app("Another Page", something_else)
app.run()

I’m using a file called multiapp that has the following code

"""Frameworks for running multiple Streamlit applications as a single app.
"""
import streamlit as st

class MultiApp:
    """Framework for combining multiple streamlit applications."""
    def __init__(self):
        self.apps = []

    def add_app(self, title, func):
        """Adds a new application."""
        self.apps.append({
            "title": title,
            "function": func
        })

    def run(self):
        app = st.sidebar.radio(
            'Go To',
            self.apps,
            format_func=lambda app: app['title'])

        app['function']()