code: def worker_task(work_item, config):
      
      global _workspace
  
      _ensure_workspace(config)
  
      result = worker(
          work_item.module_path,
          config.python_version,
          work_item.operator_name,
          work_item.occurrence,
          config.test_command,
          config.timeout)
      return work_item.job_id, result
docs: The celery task which performs a single mutation and runs a test suite.
  
      This runs `cosmic-ray worker` in a subprocess and returns the results,
      passing `config` to it via stdin.
  
      Args:
          work_item: A dict describing a WorkItem.
          config: The configuration to use for the test execution.
  
      Returns: An updated WorkItem