code: def _wait_for_consistency(checker):
      
      for _ in xrange(EVENTUAL_CONSISTENCY_MAX_SLEEPS):
          if checker():
              return
  
          time.sleep(EVENTUAL_CONSISTENCY_SLEEP_INTERVAL)
  
      logger.warning('Exceeded wait for eventual GCS consistency - this may be a'
                     'bug in the library or something is terribly wrong.')
docs: Eventual consistency: wait until GCS reports something is true.
  
      This is necessary for e.g. create/delete where the operation might return,
      but won't be reflected for a bit.