code: def dump_data(self):
      return self._submitted_subtask_ids
  
imports: import asyncio
  import pytest
  from collections import defaultdict
  from typing import Tuple, List
  from .....None import oscar
  from .....resource import Resource
  from ....cluster import ClusterAPI
  from ....cluster.core import NodeRole, NodeStatus
  from ....cluster.uploader import NodeInfoUploaderActor
  from ....cluster.supervisor.locator import SupervisorPeerLocatorActor
  from ....cluster.supervisor.node_info import NodeInfoCollectorActor
  from ....subtask import Subtask
  from ...supervisor import AssignerActor, SubtaskManagerActor, SubtaskQueueingActor, GlobalResourceManagerActor
label_desc: Use image node_id 3 for calling the MockSubtaskManagerActor obj's underlying member method code with example usage: obj.dump_data() and returns: self