How to set the Transaction expiryheight to be unlimited

Hi,

Is it possible to set the expiryheight to be unlimited when generating a zcash transaction?

It says here that this is possible by setting the expiration to be 0, but I couldn’t find how to configure this.

I tried to call the createrawtransaction rpc method by passing 0 as below:

raw_tx = self.rpc.createrawtransaction(in_txn, outputs, 0, 0)

But it looks like the minimum for the expiryheight in the createrawtransaction is 4.