Hey @Charly-Isabella, welcome to the Streamlit forums!
I tried running your code snippet and can’t reproduce the error. But after looking at the traceback you provided and doing a little more research, I think this is a Keras issue related to version 2.3.0 of Keras.
Is that the version you’re using? If so, can you try 2.2.5 or 2.3.1?
See this related Stack Overflow question for more info: https://stackoverflow.com/a/58023399
Otherwise, if this doesn’t fix your issue, would it be possible to share a more complete code snippet that includes the Keras part?
Thanks!