Sending Info to Custom Module Using Function

Sending Info to Custom Module Using Function

Hi, 

I have set up a custom module called "Entities" in Zoho CRM. Each Entity record can be linked to several Product Records. 

I want to write a function which will sum the "Amount" fields from every Product record associated with the Entity and then update the "Total Entity MRR" field in the Entity Record with the total. I have already written a function which does a similar thing with Accounts and Products which works well, but I can't seem to get it to work with Entities. This is the code I have so far: 

resp = zoho.crm.getRelatedRecords("Products","Entities",EntityId.toLong());
//info resp;
total = 0.0;
for each  rec in resp
{
total = total + ifnull(rec.get("Amount"),"0.0").toDecimal();
}
info total;
updateResp = zoho.crm.updateRecord("Entities",EntityId.toLong(),{"Total_Entity_MRR":total});
info updateResp;

Would someone be able to assist with this?