Yeah, I was wondering about that. I provided both because I wasn't sure if you could ever provide both methods of auth in the same request. If we can only ever provide one then we can totally auth based on typeof being `'string'` or `'object'`. If they auth twice, I will have override the previous auth method then.

```javascript
var drive = google.drive('v2').auth(authClient).auth('APIKEY');

drive.authClient; // will be null
drive.apiKey; // will be 'APIKEY'
```