class_docstr: Class for managing threads which run concurrent Spark jobs.
  
  This maintains a primary dispatcher thread, plus 1 thread per Hyperopt trial.
  Each trial's thread runs 1 Spark job with 1 task.
code: def _get_traceback(err):
      return err.__dict__.get("_tb_str")
  
imports: import copy
  import os
  import threading
  import time
  import timeit
  import traceback
  from hyperopt import base, fmin, Trials
  from hyperopt.base import validate_timeout, validate_loss_threshold, STATUS_OK
  from hyperopt.utils import coarse_utcnow, _get_logger, _get_random_id
label_desc: Use image node_id 4 for calling the _SparkFMinState obj's underlying member method code with example usage: obj._get_traceback(err) and returns: err