code: def add_task(self, task, parent_task_result):
          
          self.tasks.append((task, parent_task_result))
          self.task_id_to_task[task.id] = task
docs: Add a task to run with the specified result from this tasks parent(can be None)
          :param task: Task: task that should be run
          :param parent_task_result: object: value to be passed to task for setup