Page 122, Item 46, line 9 from bottom

```
p = s.client(q, r).booking(x).period(y, checkout(z)).duration();
```
should be read as
```
d = s.client(q, r).booking(x).period(y, checkout(z)).duration();
```

This makes the assignment consistent with the refactored code that follows it.

Thanks to: Toshiaki Kurokawa