code: def cancel_all_orders(self, symbol=None):
          
          data = {}
          if symbol is not None:
              data['symbol'] = symbol
          return self._delete('orders', True, data=data)
docs: Cancel all orders
  
          https://docs.kucoin.com/#cancel-all-orders
  
          .. code:: python
  
              res = client.cancel_all_orders()
  
          :returns: ApiResponse
  
          .. code:: python
  
              {
                  "cancelledOrderIds": [
                      "5bd6e9286d99522a52e458de"
                  ]
              }
  
          :raises: KucoinResponseException, KucoinAPIException