code: def req_withdraw(self, address, amount, currency, fee=0, addr_tag="", _async=False):
          
          params = {
              'address': address,
              'amount': amount,
              'currency': currency,
              'fee': fee,
              'addr-tag': addr_tag
          }
          path = '/v1/dw/withdraw/api/create'
  
          return api_key_post(params, path, _async=_async)
docs: 申请提现虚拟币
          :param address:
          :param amount:
          :param currency:btc, ltc, bcc, eth, etc ...(火币Pro支持的币种)
          :param fee:
          :param addr_tag:
          :return: {
                    "status": "ok",
                    "data": 700
                  }