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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def cancel_all_orders(self, symbol=None):
 """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 """

        data = {}
        if symbol is not None:
            data['symbol'] = symbol
        return self._delete('orders', True, data=data)