class_docstr: A mutable mapping data structure which compares using "is".
  
  This is necessary because we have trackable objects (_ListWrapper) which
  have behavior identical to built-in Python lists (including being unhashable
  and comparing based on the equality of their contents by default).
class_docstr_tok: ["A","mutable","mapping","data","structure","which","compares","using","``","is","''",".","This","is","necessary","because","we","have","trackable","objects","(","_ListWrapper",")","which","have","behavior","identical","to","built-in","Python","lists","(","including","being","unhashable","and","comparing","based","on","the","equality","of","their","contents","by","default",")","."]
code: def __iter__(self):
      for key in self._storage:
          yield key.unwrapped
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  import weakref
label_desc: Use image node_id 7 for calling the ObjectIdentityDictionary obj's underlying member method code with example usage: obj.__iter__() without return types