The sphinx doc build is now failing, because ``Implementation`` is not a valid section name.  Docstring sections have to follow a specific form laid out in the [documentation guidelines/rules](http://docs.astropy.org/en/latest/development/docrules.html).  Fortunately, this is pretty easy to fix - just replace ``Implementation`` here with ``Notes``, and remove the ``Note`` below in line 78 (perhaps also add a quick word or two indicating the current "Note" is a new topic, as they will now both appear in the same section).