TypeError: Member "trade" not found

[nance2uiuc]

From the docs, we are instructed to implement the following function in our contract:

function swapEtherToTokenWithChange (KyberNetworkProxyInterface _kyberNetworkProxy, ERC20 token, address destAddress, uint maxDestQty, uint minRate) public payable{
        //note that this.balance has increased by msg.value before the execution of this function
        uint startEthBalance = this.balance;
        
        //send swapped tokens to dest address. change will be sent to this contract.
        _kyberNetworkProxy.trade.value(msg.value)(ETH_TOKEN_ADDRESS, msg.value, token, destAddress, maxDestQty, minRate, 0);
        
        //calculate contract starting ETH balance before receiving msg.value (startEthBalance - msg.value)
        //change = current balance after trade - starting ETH contract balance (this.balance - (startEthBalance - msg.value))
        uint change = this.balance - (startEthBalance - msg.value);
        SwapEtherChange(startEthBalance, this.balance, change);
        
        //return change to get_sender()
        get_sender().transfer(change); //get_sender()
    }

However, this gives a compile error : TypeError: Member "trade" not found or not visible after argument-dependent lookup in contract KyberNetworkProxyInterface

Indeed, when the KyberNetworkProxyInterface.sol contract is inspected, it does not have a trade() method, only a tradeWithHint() method.

Changing KyberNetworkProxyInterface to KyberNetworkProxy in ...swapEtherToTokenWithChange (KyberNetworkProxyInterface _kyberNetworkProxy,... does not result in a type error.

[andrewsource147]

I doubt about that. You can check kyber smart contract in etherscan, It has trade function:
https://etherscan.io/address/0x818e6fecd516ecc3849daf6845e3ec868087b755#writeContract