code: def _setup_file_hierarchy_limit(
              self, files_count_limit, files_size_limit, temp_dir, cgroups, pid_to_kill):
          
          if files_count_limit is not None or files_size_limit is not None:
              file_hierarchy_limit_thread = FileHierarchyLimitThread(
                  self._get_result_files_base(temp_dir),
                  files_count_limit=files_count_limit,
                  files_size_limit=files_size_limit,
                  cgroups=cgroups,
                  pid_to_kill=pid_to_kill,
                  callbackFn=self._set_termination_reason,
                  kill_process_fn=self._kill_process)
              file_hierarchy_limit_thread.start()
              return file_hierarchy_limit_thread
          return None
docs: Start thread that enforces any file-hiearchy limits.