Document 1.5.2+ aspects of the NotANumber exception.  (Note that this is in the development branch, not the maintenance branch!)
Document 1.5.2+ aspects of the NotANumber exception.  (Note that this
is in the development branch, not the maintenance branch!)

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