def withdraw(currency_code, address, amount, option = {})
            option["currency"] = currency_code
            option["address"] = address
            option["amount"] = amount
            json = post_ssl(@zaif_trade_url, "withdraw", option)
            return json
        end
def withdraw(currency_code, address, amount, option = {})
            option["currency"] = currency_code
            option["address"] = address
            option["amount"] = amount
            json = post_ssl(@zaif_trade_url, "withdraw", option)
            return json
        end
Withdraw funds.
 Need api key.