How to use the mutagen.ogg.OggPage function in mutagen

# Use it to get the serial number.
        page = OggPage(fileobj)
        while not page.packets[0].startswith(b"Speex   "):
            page = OggPage(fileobj)

        # Look for the next page with that serial number, it'll start
        # the comment packet.
        serial = page.serial
        page = OggPage(fileobj)
        while page.serial != serial:
            page = OggPage(fileobj)

        # Then find all the pages with the comment packet.
        old_pages = [page]
        while not (old_pages[-1].complete or len(old_pages[-1].packets) > 1):
            page = OggPage(fileobj)
            if page.serial == old_pages[0].serial:
                old_pages.append(page)

        packets = OggPage.to_packets(old_pages, strict=False)

        content_size = get_size(fileobj) - len(packets[0])  # approx
        vcomment_data = self.write(framing=False)
        padding_left = len(packets[0]) - len(vcomment_data)

        info = PaddingInfo(padding_left, content_size)
        new_padding = info._get_padding(padding_func)

        # Set the new comment packet.
        packets[0] = vcomment_data + b"\x00" * new_padding

        new_pages = OggPage._from_packets_try_preserve(packets, old_pages)

def __init__(self, fileobj):
        page = OggPage(fileobj)
        while not page.packets[0].startswith(b"OpusHead"):
            page = OggPage(fileobj)

        self.serial = page.serial

        if not page.first:
            raise OggOpusHeaderError(
                "page has ID header, but doesn't start a stream")

        (version, self.channels, pre_skip, orig_sample_rate, output_gain,
         channel_map) = struct.unpack("> 4, version & 0xF

if page.size < default_size and len(page.packets) < 255:
                    page.packets[-1] += data
                else:
                    # If we've put any packet data into this page yet,
                    # we need to mark it incomplete. However, we can
                    # also have just started this packet on an already
                    # full page, in which case, just start the new
                    # page with this packet.
                    if page.packets[-1]:
                        page.complete = False
                        if len(page.packets) == 1:
                            page.position = -1
                    else:
                        page.packets.pop(-1)
                    pages.append(page)
                    page = OggPage()
                    page.continued = not pages[-1].complete
                    page.sequence = pages[-1].sequence + 1
                    page.packets.append(data)

                if len(packet) < wiggle_room:
                    page.packets[-1] += packet
                    packet = b""

        if page.packets:
            pages.append(page)

        return pages

def __init__(self, fileobj):
        page = OggPage(fileobj)
        while not page.packets[0].startswith(b"OpusHead"):
            page = OggPage(fileobj)

        self.serial = page.serial

        if not page.first:
            raise OggOpusHeaderError(
                "page has ID header, but doesn't start a stream")

        (version, self.channels, pre_skip, orig_sample_rate, output_gain,
         channel_map) = struct.unpack("> 4

def __get_comment_pages(self, fileobj, info):
        # find the first tags page with the right serial
        page = OggPage(fileobj)
        while ((info.serial != page.serial) or
                not page.packets[0].startswith(b"OpusTags")):
            page = OggPage(fileobj)

        # get all comment pages
        pages = [page]
        while not (pages[-1].complete or len(pages[-1].packets) > 1):
            page = OggPage(fileobj)
            if page.serial == pages[0].serial:
                pages.append(page)

        return pages

"""Write tag data into the Vorbis comment packet/page."""

        # Find the old pages in the file; we'll need to remove them,
        # plus grab any stray setup packet data out of them.
        fileobj.seek(0)
        page = OggPage(fileobj)
        while not page.packets[0].startswith(b"\x03vorbis"):
            page = OggPage(fileobj)

        old_pages = [page]
        while not (old_pages[-1].complete or len(old_pages[-1].packets) > 1):
            page = OggPage(fileobj)
            if page.serial == old_pages[0].serial:
                old_pages.append(page)

        packets = OggPage.to_packets(old_pages, strict=False)

        content_size = get_size(fileobj) - len(packets[0])  # approx
        vcomment_data = b"\x03vorbis" + self.write()
        padding_left = len(packets[0]) - len(vcomment_data)

        info = PaddingInfo(padding_left, content_size)
        new_padding = info._get_padding(padding_func)

        # Set the new comment packet.
        packets[0] = vcomment_data + b"\x00" * new_padding

        new_pages = OggPage._from_packets_try_preserve(packets, old_pages)
        OggPage.replace(fileobj, old_pages, new_pages)

packets = OggPage.to_packets(old_pages)
        vcomment_data = b"OpusTags" + self.write(framing=False)

        if self._pad_data:
            # if we have padding data to preserver we can't add more padding
            # as long as we don't know the structure of what follows
            packets[0] = vcomment_data + self._pad_data
        else:
            content_size = get_size(fileobj) - len(packets[0])  # approx
            padding_left = len(packets[0]) - len(vcomment_data)
            info = PaddingInfo(padding_left, content_size)
            new_padding = info._get_padding(padding_func)
            packets[0] = vcomment_data + b"\x00" * new_padding

        new_pages = OggPage._from_packets_try_preserve(packets, old_pages)
        OggPage.replace(fileobj, old_pages, new_pages)

def _inject(self, fileobj):
        """Write tag data into the Speex comment packet/page."""

        fileobj.seek(0)

        # Find the first header page, with the stream info.
        # Use it to get the serial number.
        page = OggPage(fileobj)
        while not page.packets[0].startswith("Speex   "):
            page = OggPage(fileobj)

        # Look for the next page with that serial number, it'll start
        # the comment packet.
        serial = page.serial
        page = OggPage(fileobj)
        while page.serial != serial:
            page = OggPage(fileobj)

        # Then find all the pages with the comment packet.
        old_pages = [page]
        while not (old_pages[-1].complete or len(old_pages[-1].packets) > 1):
            page = OggPage(fileobj)
            if page.serial == old_pages[0].serial:
                old_pages.append(page)

page = OggPage(fileobj)

        old_pages = [page]
        while not (old_pages[-1].complete or len(old_pages[-1].packets) > 1):
            page = OggPage(fileobj)
            if page.serial == first_page.serial:
                old_pages.append(page)

        packets = OggPage.to_packets(old_pages, strict=False)

        # Set the new comment block.
        data = self.write(framing=False)
        data = packets[0][:1] + struct.pack(">I", len(data))[-3:] + data
        packets[0] = data

        new_pages = OggPage.from_packets(packets, old_pages[0].sequence)
        OggPage.replace(fileobj, old_pages, new_pages)

fileobj.seek(0)
        page = OggPage(fileobj)
        while not page.packets[0].startswith("\x81theora"):
            page = OggPage(fileobj)

        old_pages = [page]
        while not (old_pages[-1].complete or len(old_pages[-1].packets) > 1):
            page = OggPage(fileobj)
            if page.serial == old_pages[0].serial:
                old_pages.append(page)

        packets = OggPage.to_packets(old_pages, strict=False)

        packets[0] = "\x81theora" + self.write(framing=False)

        new_pages = OggPage.from_packets(packets, old_pages[0].sequence)
        OggPage.replace(fileobj, old_pages, new_pages)