docs: def get_current_state_m(self):
          """Returns the state model of the currently open tab"""
          page_id = self.view.notebook.get_current_page()
          if page_id == -1:
              return None
          page = self.view.notebook.get_nth_page(page_id)
          state_identifier = self.get_state_identifier_for_page(page)
          return self.tabs[state_identifier]['state_m']