Uncaught Error: Can't find config

```
<link rel="stylesheet" type="text/css" href="/assets/pen/pen.css" />
<script src="/assets/pen/pen.js"></script>
<script src="/assets/pen/markdown.js"></script>

<script type="text/javascript">
  var editor = new Pen(document.getElementById('my_elem'));
</script>


```

Error:

```
pen.js:485 Uncaught Error: Can't find config
    at new Pen (pen.js:485)
    at edit:102
```