Cleans the ETag as returned by :func:`get_etag`. Will wrap it in
        quotes and append the extension for the current MIME type.

def clean_etag(self, etag):
        """Cleans the ETag as returned by :func:`get_etag`. Will wrap it in
        quotes and append the extension for the current MIME type.
        """
        if etag:
            etag = etag.replace('"', '')
            extension = None
            for ext, mime in self.EXTENSION_MAP:
                if mime == self.type:
                    extension = ext[1:]
                    break
            if extension:
                etag += '_' + extension
            self.response.etag = etag