def freeze(self, no_etag=False):
        """Call this method if you want to make your response object ready for
        pickeling.  This buffers the generator if there is one.  This also
        sets the etag unless `no_etag` is set to `True`.
        """
        if not no_etag:
            self.add_etag()
        super(ETagResponseMixin, self).freeze()