Cant generate sub tasks

Hi Team,

  I want to generate subprocesses dynamically and call the usertask of that subprocess for this

In bpmn i used bpmn:loopCardinality${numprocess}
</bpmn:loopCardinality>

And in my ProcessService class
taskVariables.put(“numprocess”,“3”);
SetactionAssignees=new Hashset<>()
actionAssignees.add(“mumbai”)
actionAssignees.add(“delhi”)
actionAssignees.add(“pune”)

taskVariables.put(“actionAssignees”,actionAssignees)

System.out.println(task.getName()+""+""+task.getAssignee())

I am getting assignees as null values…