I need to deselect the option contract and trade with the underlying.

I found this in the manual:

--------- MANUAL -------------
contract (int Type, int Expiry, var Strike): CONTRACT*
...Calling asset, contractUpdate, or contract(0) deselects the contract and allows again trading with the underlying.
--------- MANUAL END ---------

However, when I use "contract(0);", Zorro says "wrong number of parameters". When I use "contract(0,0,0);", then it says Invalid contract parameters and the last contract is not deselected.

The second option, calling contractUpdate, also doesn't deselect the contract.

So I tried to use asset("SPY"); and it works, but I am not sure it's the best way.

How should I call contract(0) or contractUpdate to deselect the contract?