How to use the pympress.document.Document function in pympress

if response == gtk.RESPONSE_OK:
			name =  dialog.get_filename()
		elif response != gtk.RESPONSE_CANCEL:
			raise ValueError("Invalid response")

		dialog.destroy()

	if name is None:
		# Use a GTK dialog to tell we need a file
		msg="""No file selected!\n\nYou can specify the PDF file to open on the command line if you don't want to use the "Open File" dialog."""
		dialog = gtk.MessageDialog(type=gtk.MESSAGE_ERROR, buttons=gtk.BUTTONS_OK, message_format=msg)
		dialog.set_position(gtk.WIN_POS_CENTER)
		dialog.run()
		sys.exit(1)
	else:
		doc = pympress.document.Document("file://" + name)
		doc.run()

def swap_document(self, docpath, page = 0, reloading = False):
        """ Replace the currently open document with a new one.

        The new document is possibly and EmptyDocument if docpath is None.
        The state of the ui and cache are updated accordingly.

        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')

wh (`int`):  target height in pixels
            dtype (:class:`~pympress.document.PdfPage`):  the type of document that should be rendered
        """
        pass


    def can_render(self):
        """ Informs that rendering is *not* necessary (avoids checking the type).

        Returns:
            `bool`: `False`, no rendering
        """
        return False


class EmptyDocument(Document):
    """ A dummy document, placeholder for when no document is open.
    """

    def __init__(self):
        self.path = None
        self.doc = None
        self.nb_pages = 0
        self.cur_page = -1
        self.pages_cache = {-1: EmptyPage()}
        self.notes = False


    def page(self, number):
        """ Retrieve a page from the document.

        Args:

""" Initializes a Document by passing it a :class:`~Poppler.Document`.

        Args:
            builder (:class:`pympress.builder.Builder`):  A builder to load callbacks
            path (`str`):  Absolute path to the PDF file to open
            page (`int`):  page number to which the file should be opened

        Returns:
            :class:`~pympress.document.Document`: The initialized document
        """
        if path is None:
            doc = EmptyDocument()
        else:
            uri = Document.path_to_uri(path)
            poppler_doc = Poppler.Document.new_from_file(uri, None)
            doc = Document(builder, poppler_doc, path, page)

        return doc

def create(builder, path, page=0):
        """ Initializes a Document by passing it a :class:`~Poppler.Document`.

        Args:
            builder (:class:`pympress.builder.Builder`):  A builder to load callbacks
            path (`str`):  Absolute path to the PDF file to open
            page (`int`):  page number to which the file should be opened

        Returns:
            :class:`~pympress.document.Document`: The initialized document
        """
        if path is None:
            doc = EmptyDocument()
        else:
            uri = Document.path_to_uri(path)
            poppler_doc = Poppler.Document.new_from_file(uri, None)
            doc = Document(builder, poppler_doc, path, page)

        return doc