def on_markdown_table_of_contents_updated(
        self, event: Markdown.TableOfContentsUpdated
    ) -> None:
        """Handle the table of contents of the document being updated.

        Args:
            event: The table of contents update event to handle.
        """
        # We don't handle this, the navigation pane does. Bounce the event
        # over there.
        self.query_one(Navigation).table_of_contents.on_table_of_contents_updated(event)
Handle the table of contents of the document being updated.

        Args:
            event: The table of contents update event to handle.
        
frogmouth/screens/main.py