class_docstr: Error which happen during evaluation of submission.
  
  To simplify error handling, worker only raises this type of exception.
  Exceptions of different types raised by other modules encapsulated
  into WorkerError by the worker.
class_docstr_tok: ["Error","which","happen","during","evaluation","of","submission",".","To","simplify","error","handling",",","worker","only","raises","this","type","of","exception",".","Exceptions","of","different","types","raised","by","other","modules","encapsulated","into","WorkerError","by","the","worker","."]
docstr: Returns human readable string representation of the exception.
docstr_tok: ["Returns","human","readable","string","representation","of","the","exception","."]
code: def __str__(self):
      """Returns human readable string representation of the exception."""
      if self.exc:
          return "{0}\nUnderlying exception:\n{1}".format(
              self.msg, self.exc
          )
      else:
          return self.msg
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  from builtins import int
  import argparse
  import json
  import logging
  import os
  import random
  import shutil
  import subprocess
  import time
  import uuid
  from six import iteritems
  import eval_lib
  from cleverhans.utils import shell_call
label_desc: Use image node_id 2 for calling the WorkerError obj's underlying member method code with example usage: obj.__str__() and returns: str, self