class_docstr: User-facing API for accessing the NASBench dataset.
docstr: Returns iterator over all unique model hashes.
docstr_tok: ["Returns","iterator","over","all","unique","model","hashes","."]
code: def hash_iterator(self):
      """Returns iterator over all unique model hashes."""
      return self.fixed_statistics.keys()
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  import copy
  import random
  import time
  import shelve
  import hashlib
  import _pickle
  import numpy
label_desc: Use image node_id 6 for calling the NASBench obj's underlying member method code with example usage: obj.hash_iterator() and returns: self