Custom CRM to close task when lead lost

Hello,

I am currently trying to create a workflow rule to close the tasks still opens of the lost leads.

I tried the workflowrule and update the field but it does not work because they come from 2 different modules (task and lead).

So I tried to write a function that does not work also. Can you tell me what's wrong with that or anything else?

here the function,

if(status.contains("Junk"))

{

leadIdStr = leadId.toString();

relatedTask = zoho.crm.v1.getRelatedRecords("Tasks","Leads",leadIdStr);

for each task in relatedTask

{

mapVariable = Map();

mapVariable.put("Status","Completed");

taskID = task.get("ACTIVITYID");

taskIdStr = taskID.toString();

updateTask = zoho.crm.v1.updateRecord("Tasks",taskIdStr,mapVariable);

}