Connecting Python to a webpage via node-red

Please check your settings.js file — do you have a url prefix defined for either httpRoot or httpNodeRoot?

For instance, in my project, when I add a new websocket config node, this info box is shown:

By default, payload will contain the data to be sent over, or received from a
websocket. The listener can be configured to send or receive the entire message
object as a JSON formatted string. This path will be relative to /red.

If so, I believe you will have to modify the url in your python code, like so:
ws.connect("ws://localhost:1880/red/ws/example")

substituting your prefix, of course…