code: def is_unclaimed(work):
      """Returns True if work piece is unclaimed."""
      if work["is_completed"]:
          return False
      cutoff_time = time.time() - MAX_PROCESSING_TIME
      if (
          work["claimed_worker_id"]
          and work["claimed_worker_start_time"] is not None
          and work["claimed_worker_start_time"] >= cutoff_time
      ):
          return False
      return True
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  from builtins import int
  from io import StringIO
  import pickle
  import random
  import time
  import numpy
  from six import iteritems
  from six import itervalues
  from six import text_type
label_desc: Use image node_id 2 for calling a global function with example usage: is_unclaimed(work) and returns: True, False, False