class _Message(object):

    """A message returned by ``Flash.pop_messages()``.

    Converting the message to a string returns the message text. Instances

    also have the following attributes:

    * ``message``: the message text.

    * ``category``: the category specified when the message was created.

    """

    def __init__(self, category, message):

        self.category=category

        self.message=message

    def __str__(self):

        return self.message

    __unicode__ = __str__

    def __html__(self):

        return escape(safe_unicode(self.message))

class Flash(_Flash):

    def pop_messages(self):

        """Return all accumulated messages and delete them from the session.

        The return value is a list of ``Message`` objects.

        """

        from pylons import session

        messages = session.pop(self.session_key, [])

        session.save()

        return [_Message(*m) for m in messages]

flash = Flash()