Please put the note about ignoring Xcode warnings before the code.
The bottom of page 66 adds three func overrides which Xcode declares in error. The “fix” is on page 67. I spent ten minutes trying to figure what I did wrong only to eventually discover the warning on the next page.
The warning should be first saying something like you are going to add three pieces of code and ignore Xcode errors/warnings until all the code is in place.