Hello, I think this is incorrect.

The example is sending `curl http://localhost:4567/tokens -d number=` (setting number to nothing) and the second line is the output of the command: `{"error":{"param":"number","type":"presence"}`

Your modification made it a single line, which is incorrect.

A better block will be:

```
$ curl http://localhost:4567/tokens -d number=
{"error":{"param":"number","type":"presence"}}
```

(it is missing one `}`)