//LeadId = 4857358000014515001;
optionalMp = Map();
optionalMp.put("sort_by","Due_Date");
optionalMp.put("sort_order","asc");   
related_tasks = zoho.crm.getRelatedRecords("Tasks","Leads",LeadId,1,200,optionalMp);
for each  task in related_tasks
{
    //             info task.get("Due_Date");
    //             info task.get("Status");
    if(task.get("Status") == "Not Started")
    {
        related_tasksId = task.get("id");
        update = zoho.crm.updateRecord("Tasks",related_tasksId,{"Status":"Completed"});
        info update;
    }
    break;
}
mp = Map();
mp.put("Subject","Test Task");
mp.put("Due_Date",today.toString("yyyy-MM-dd"));
mp.put("Status","Not Started");
mp.put("$se_module","Leads");
mp.put("Subject","My new Test Task");
mp.put("Description","Task created make a reminder after 7 days of current date");
mp.put("What_Id",LeadId);
mp.put("Owner",leadowner);
create = zoho.crm.createRecord("Tasks",mp);
info create;