AttributeError: st.session_state has no attribute “key”. Did you forget to initialize it?

import streamlit as st

if 'key' not in st.session_state:
    st.session_state['key'] = 'value'

# Update session state
st.session_state['key'] = 'value4'

# Read session state
st.write(st.session_state['key'])

 

해당 코드를 .py 로 저장하기(파일명 예시 : streamlit_app.py)

 

터미널에서 streamlit 실행하기

 

streamlit run streamlit_app.py