According to Django documentation I've registered my filter:

```
from google.appengine.ext.webapp import template
# ...
register = template.create_template_register()
@register.filter(name='wld')
def wld(result):
    if result == 1 : return "win"
    if result == 0 : return "loss"
    if result == 0.5 : return "draw"
    return "unknown"
self.response.out.write(template.render("player.html", template_values))

```

somewhere in the template I have code:  

`{{result|wld}}` 

and when I try to render my template, I get the error: `TemplateSyntaxError: Invalid filter: 'wld'`

What am I doing wrong?