How to update a Python class instance plot attribute from button callback?

I’m trying to update a plot from button callback. The callback supposedly works according to my test prints but the plot in the served app is not updated. How to go about updating the plot also to the app and not only to the Python class instance? I read from a previous post that layouts such as Column should be updatable and I have the class attributes including the plot I want to update in a Column. The Column is inside a tab which is inside a template. Is that a problem?

For future reference: self.tabs.__setitem__(tab_index, new_value) where self.tabs is a pn.Tabs instance solved the updating probelm in my case. There seems to be no instructions for using the __setitem__-method on the Panel webiste. I was lucky to bump into a similar question with a code snippet.