Remove the Py_FatalError() from initpyexpat(); the Guido has decreed that this is not appropriate.
Remove the Py_FatalError() from initpyexpat(); the Guido has decreed
that this is not appropriate.

Made somewhat more robust in the face of reload() (exception is not
rebuilt, etc.).

Made the exception a class exception.

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