class_docstr: A subclass of pickler, to do cryptographic hashing, rather than
  pickling.
class_docstr_tok: ["A","subclass","of","pickler",",","to","do","cryptographic","hashing",",","rather","than","pickling","."]
code: def memoize(self, obj):
      # We want hashing to be sensitive to value instead of reference.
      # For example we want ['aa', 'aa'] and ['aa', 'aaZ'[:2]]
      # to hash to the same value and that's why we disable memoization
      # for strings
      if isinstance(obj, _bytes_or_unicode):
          return
      Pickler.memoize(self, obj)
  
imports: import pickle
  import hashlib
  import sys
  import types
  import struct
  import io
  import decimal
  from ._compat import _bytes_or_unicode, PY3_OR_LATER
label_desc: Use image node_id 4 for calling the Hasher obj's underlying member method code with example usage: obj.memoize(obj) without return types