ID vs. Class in Accordeon API-Doc

On `http://api.jqueryui.com/accordion/`
the Example states 
```
<div id="accordion">
  <h3>First header</h3>
  <div>First content panel</div>
  <h3>Second header</h3>
  <div>Second content panel</div>
</div>
```

But the node `#accordion` is always referenced as ".accordion" in later steps.
For example:
```
$( ".selector" ).accordion({
  active: 2
});
```