Page flow

flow.py

import streamlit as st

class App():
    def __init__(self, default=None):
        self.page = default
        self.args = []
        self.kwargs = {}

    def goto(self, page, *args, **kwargs):
        self.page = page
        self.args = args
        self.kwargs = kwargs
        st.rerun()

    def next(self, page, *args, **kwargs):
        self.page = page

    def go(self):
        st.rerun()

    def show(self):
        self.page(*self.args, **self.kwargs)

def initialize(key, default):
    if key not in st.session_state:
        st.session_state[key] = default()