Return a sequence of directory paths on a Mac in which fonts are
        likely to be located.

def _os_x_font_directories(cls):
        """
        Return a sequence of directory paths on a Mac in which fonts are
        likely to be located.
        """
        os_x_font_dirs = [
            '/Library/Fonts',
            '/Network/Library/Fonts',
            '/System/Library/Fonts',
        ]
        home = os.environ.get('HOME')
        if home is not None:
            os_x_font_dirs.extend([
                os.path.join(home, 'Library', 'Fonts'),
                os.path.join(home, '.fonts')
            ])
        return os_x_font_dirs