<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def create_withdrawal(self, currency, amount, address, memo=None, is_inner=False, remark=None):
 """Process a withdrawal https://docs.kucoin.com/#apply-withdraw :param currency: Name of currency :type currency: string :param amount: Amount to withdraw :type amount: number :param address: Address to withdraw to :type address: string :param memo: (optional) Remark to the withdrawal address :type memo: string :param is_inner: (optional) Remark to the withdrawal address :type is_inner: bool :param remark: (optional) Remark :type remark: string .. code:: python withdrawal = client.create_withdrawal('NEO', 20, '598aeb627da3355fa3e851') :returns: ApiResponse .. code:: python { "withdrawalId": "5bffb63303aa675e8bbe18f9" } :raises: KucoinResponseException, KucoinAPIException """


        data = {
            'currency': currency,
            'amount': amount,
            'address': address
        }

        if memo:
            data['memo'] = memo
        if is_inner:
            data['isInner'] = is_inner
        if remark:
            data['remark'] = remark

        return self._post('withdrawals', True, data=data)