01_🏠_page.py

import streamlit as st

def _progress():
    form_fields = st.session_state['form_fields']
    return sum([bool(x) for x in form_fields.values()]) / len(form_fields)

if 'form_fields' not in st.session_state:
    st.session_state['form_fields'] = {
        'page_1_a': None,
        'page_1_b': None,
        'page_2_a': None,
        'page_2_b': None
    }
    st.session_state['progress'] = _progress

st.sidebar.progress(st.session_state['progress']())

st.json(st.session_state['form_fields'])