Django snippets

class SessionMessageContainer:
    """
        In a view create messages with:
        SessionMessageContainer.append_to_session(request.session, u"Order with id: %s saved"%order.id)

        Output in template with:
        <ul class="messagelist">
            {% for message in request.session.messages.get_and_clear %}
            <li>{{message}}</li>
            {% endfor %}
        </ul>
    """
    def append(self, message):
        self.messages.append(message)
    def get_and_clear(self):
        from django.contrib.sessions.backends.db import SessionStore
        messages = self.messages
        self.messages=[]
        s = SessionStore(session_key=self.key)
        s['messages']=self
        s.save()
        return messages
    def __init__(self, key):
        self.key = key
        self.messages = []
    @staticmethod
    def append_to_session(session, message):
        messages = session.get('messages', SessionMessageContainer(key=session.session_key))
        messages.append(message)
        session['messages']=messages