If layout.hovermode='x' (or 'y'), a single hover label appears per trace, for points at the same x (or y) value as the cursor. If multiple points in a given trace exist at the same coordinate, only ...

The following cell is not shown either in the book. It creates the images/end_to_end_project folder (if it doesn't already exist), and it defines the save_fig() function which is used through this ...