Return MacOS.Error in stead of RuntimeError in case of failure so the user gets a reasonable explanation in stead of a large negative number.
Return MacOS.Error in stead of RuntimeError in case of failure so the user
gets a reasonable explanation in stead of a large negative number.

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