Need help with Update field values using Custom Functions and Workflow

Need help with Update field values using Custom Functions and Workflow

Hi, am stuck for a couple of days now, read lots of tutorials and posts in here.

Am trying to update a field in Account (Priorit_entreprise) to Contact (Priorit) with this function

rec = zoho.crm.getRecordById("Accounts",acctId);
mp = Map();
mp.put("Priorit_entreprise",ifnull(rec.get("Priorit"),""));
updateResp = zoho.crm.updateRecord("Contacts",contId,mp,{"trigger":{"workflow"}});
info updateResp;

In all the tutorials I read, you suppose to have in your arguments like this : 
contId = Contact ID (From Contacts)
acctId = Account Id (From Accounts)

I dont know why, but on my end I only have Select Type, so I choose Int.



Now when I test my function with a Contact_id (ex : 3282218000001439003) and and Account_id (ex: 3282218000001286016), my record is updated.

So nice, I created my Workflow, call my function and got that :



I tried a couple of things in Value but nothing is working. 

So, what is the value I need to put in there?

Thanks in advance!