Document the demise of all pretenses of safety, and the difference between cPickle and pickle.py regarding __safe_for_unpickling__ before Python 2.3.
Document the demise of all pretenses of safety, and the difference
between cPickle and pickle.py regarding __safe_for_unpickling__ before
Python 2.3.

sk-/python2.7-type-annotator,sk-/python2.7-type-annotator,sk-/python2.7-type-annotator