DoubleClick.refreshAds not working with multiple arguments

If I call 
`DoubleClick.refreshAds('ad-leaderboard', 'ad-leaderboard-sm', 'ad-square');`

it only refreshes the first argument, the other two are ignored.

Calling

`````` DoubleClick.refreshAds('ad-leaderboard');
DoubleClick.refreshAds('ad-leaderboard-sm');
DoubleClick.refreshAds('ad-square');```

works as expected. Not sure if it's a bug or if you want to just adjust your readme.
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