code: def close(self, code=None):
          '''return a `close` :class:`Frame`.
          '''
          code = code or 1000
          body = pack('!H', code)
          body += self._close_codes.get(code, '').encode('utf-8')
          return self.encode(body, opcode=0x8f close(self, code=None):
          '''return a `close` :class:`Frame`.
          '''
          code = code or 1000
          body = pack('!H', code)
          body += self._close_codes.get(code, '').encode('utf-8')
          return self.encode(body, opcode=0x8)
docs: return a `close` :class:`Frame`.