I'm trying to set up a button to create a new contact from a custom module. I found this code on a Zoho help page ( https://www.zoho.com/crm/help/automation/custom-function-examples.html). I made a few modifications to it based on our fields. 

CustomModuleDetails = zoho.crm.getRecordById("CustomModule15", input.customId.tolong());

ContactMap = map();

ContactMap.put("Last Name", ifnull(CustomModuleDetails.get("Contact Name"),""));

ContactMap.put("Email", ifnull(CustomModuleDetails.get("Email"),""));

ContactMap.put("Phone", ifnull(CustomModuleDetails.get("Sales Contact Phone"),""));

ContactCreate = zoho.crm._create("Contacts", ContactMap);

But whenever I try to save this code I'm getting an error:

Missing return statement: Provide STRING expression to return

Has anyone else had success in creating a button like this? Would you mind sharing the code that worked for you?