@classmethod
def get_preview_data(cls, request):
    """
        Get the preview data.

        You should use this in the preview view to get the
        data for the preview.

        You normally do not override this. If you want to manage
        serialization yourself, see :meth:`.serialize_preview`.
        """
    serialized = request.session.pop(cls.get_preview_sessionkey())
    return cls.deserialize_preview(serialized)
