What is the proper way to submit a form? (DjangoClient)

Using the Django client, I can click on a link, but when I click on a button I get:

```
self =

def click(self):
"""
Clicks in the element.
"""
> raise NotImplementedError
E NotImplementedError
```

with the element

```
elements
outer_html
Sign Up

```

Am I missing something?