Need help with Transformer RUles

Hi,

I struggle with Facebook’s Transformer Rules.

I would like to transform an ad using the class AdRule.
Here is what my code looks like :

<div id="pub-314-1">
<a href="my-url">
<img src="my-img"></img>
</a>
</div>

Here is my attempt :

    "rules":
    [{
		"class":"AdRule",
		"selector":"div.pub-314-1",
		"properties":{
			"ad.url":{
				"type":"string",
				"selector":"a",
				"attribute":"href"}
			"ad.embed":{
				"type":"string",
				"selector":"img",
				"attribute":"src"
				}
				}
	}

But nothing happens.

Any idea ? Thanks in advance.

Joffrey