docstr: Clean invalid subtask item from the queue to ensure that when the queue is not empty,
  there is always some subtasks waiting being scheduled.
docstr_tok: ["Clean","invalid","subtask","item","from","the","queue","to","ensure","that","when","the","queue","is","not","empty",",","there","is","always","some","subtasks","waiting","being","scheduled","."]
code: def _ensure_top_item_valid(self, task_queue):
      """Clean invalid subtask item from the queue to ensure that when the queue is not empty,
      there is always some subtasks waiting being scheduled."""
      while (
          task_queue
          and task_queue[0].subtask.subtask_id
          not in self._stid_to_items
      ):
          #  skip removed items (as they may be re-pushed into the queue)
          heapq.heappop(task_queue)
      return bool(task_queue)
  
imports: import asyncio
  import copy
  import heapq
  import logging
  from collections import defaultdict
  from dataclasses import dataclass
  from typing import DefaultDict, Dict, List, Optional, Tuple, Union, Set
  from ....None import oscar
  from ....lib.aio import alru_cache
  from ....metrics import Metrics
  from ....resource import ZeroResource
  from ....utils import dataslots
  from ...subtask import Subtask
  from ...task import TaskAPI
  from ..utils import redirect_subtask_errors
label_desc: Use image node_id 3 for calling the SubtaskQueueingActor obj's underlying member method code with example usage: obj._ensure_top_item_valid(task_queue) and returns: bool