How to use the pympress.document function in pympress

def main(argv = sys.argv[1:]):
    signal.signal(signal.SIGINT, signal.SIG_DFL)

    # prefere X11 on posix systems because Wayland still has some shortcomings for us,
    # specifically libVLC and the ability to disable screensavers
    if util.IS_POSIX:
        Gdk.set_allowed_backends('x11,*')
    Gtk.init(argv)

    pympress_meta = util.get_pympress_meta()['version']
    logger.info(' '.join(['Pympress:', pympress_meta,
            '; Python:', platform.python_version(),
            '; OS:', platform.system(), platform.release(), #platform.version(),
            '; Gtk {}.{}.{}'.format(Gtk.get_major_version(), Gtk.get_minor_version(), Gtk.get_micro_version()),
            '; GLib {}.{}.{}'.format(GLib.MAJOR_VERSION, GLib.MINOR_VERSION, GLib.MICRO_VERSION),
            '; Poppler', document.Poppler.get_version(), document.Poppler.get_backend().value_nick,
            '; Cairo', ui.cairo.cairo_version_string(), ', pycairo', ui.cairo.version,
            '; Media:', extras.Media.backend_version()
        ]))

    try:
        opts, args = getopt.getopt(argv, "hn:t:", ["help", "notes=", "talk-time=", "log="])
    except getopt.GetoptError:
        usage()
        sys.exit(2)

    ett, log_level, notes_pos = parse_opts(opts)
    logger.setLevel(log_level)

    # Create windows
    gui = ui.UI()

def parse_opts(opts):
    ett = 0
    log_level = logging.ERROR
    notes_pos = None

    for opt, arg in opts:
        if opt in ("-h", "--help"):
            usage()
            sys.exit()
        if opt in ("-n", "--notes"):
            if arg.lower()[0] == 'n': notes_pos = document.PdfPage.NONE
            if arg.lower()[0] == 'l': notes_pos = document.PdfPage.LEFT
            if arg.lower()[0] == 'r': notes_pos = document.PdfPage.RIGHT
            if arg.lower()[0] == 't': notes_pos = document.PdfPage.TOP
            if arg.lower()[0] == 'b': notes_pos = document.PdfPage.BOTTOM
        elif opt in ("-t", "--talk-time"):
            t = ["0" + n.strip() for n in arg.split(':')]
            try:
                m = int(t[0])
                s = int(t[1])
            except ValueError:
                print(_("Invalid time (mm or mm:ss expected), got \"{}\"").format(arg))
                usage()
                sys.exit(2)
            except IndexError:
                s = 0
            ett = m * 60 + s
        elif opt == "--log":

Args:
            docpath (`str`): the absolute path to the new document
            page (`int`): the page at which to start the presentation
            reloading (`bool`): whether we are reloading or detecting stuff from the document
        """
        try:
            self.doc = document.Document.create(self, docpath)

            if not reloading and docpath:
                Gtk.RecentManager.get_default().add_item(self.doc.get_uri())
                extras.FileWatcher.watch_file(docpath, self.reload_document)

        except GLib.Error:
            if reloading:
                return
            self.doc = document.Document.create(self, None)
            self.error_opening_file(docpath)
            extras.FileWatcher.stop_watching()

        # Guess notes mode by default if the document has notes
        if not reloading:
            hpref = self.config.get('notes position', 'horizontal')
            vpref = self.config.get('notes position', 'vertical')
            self.chosen_notes_mode = target_mode = self.doc.guess_notes(hpref, vpref)

            # don't toggle from NONE to NONE
            if self.chosen_notes_mode == document.PdfPage.NONE:
                self.chosen_notes_mode = document.PdfPage.RIGHT

            if self.notes_mode != target_mode:
                self.switch_mode('swap_document', docpath, target_mode = target_mode)