docs: def set(self, key, response):
          """Set cache entry for key with contents of response."""
          mod = response.headers.pop('last-modified', None)
          status = int(response.status_code)
          rec = (key, status, mod, response.encoding, response.content,
                 json.dumps(dict(response.headers)))
          with self._conn:
              self._conn.execute("DELETE FROM cache WHERE key=?", (key, ))
              self._conn.execute("INSERT INTO cache VALUES (?,?,?,?,?,?)", rec)