docstr: Make sure we can import torch before launching a slew of workers.
docstr_tok: ["Make","sure","we","can","import","torch","before","launching","a","slew","of","workers","."]
code: def _canary_import(self) -> None:
      """Make sure we can import torch before launching a slew of workers."""
      source_cmds: Set[str] = set()
      for w in self._work_items:
          if w.source_cmd is not None:
              source_cmds.add(f"{w.source_cmd} && ")
  
      for source_cmd in source_cmds or {""}:
          cmd = f'{source_cmd}{PYTHON_CMD} -c "import torch"'
          proc = subprocess.run(
              cmd,
              shell=True,
              stdout=subprocess.PIPE,
              stderr=subprocess.STDOUT,
              encoding="utf-8",
              executable=SHELL,
          )
  
          if proc.returncode:
              raise ImportError(
                  f"Failed to import torch in subprocess: {cmd}\n{proc.stdout}"
              )
  
imports: import math
  import multiprocessing
  import subprocess
  import textwrap
  import threading
  import time
  from typing import Dict, List, Optional, Set, Tuple, Union
  from worker.main import WorkerFailure, WorkerOutput
  from execution.work import InProgress, PYTHON_CMD, SHELL, WorkOrder
label_desc: Use image node_id 8 for calling the Runner obj's underlying member method code with example usage: obj._canary_import() without return types