How to use the mediafile.ListStorageStyle function in mediafile

items = self._fetch_unpacked(mutagen_file)
        items[self.pack_pos] = value
        if items[0] is None:
            items[0] = ''
        if items[1] is None:
            items.pop()  # Do not store last value
        self.store(mutagen_file, '/'.join(map(six.text_type, items)))

    def delete(self, mutagen_file):
        if self.pack_pos == 0:
            super(MP3SlashPackStorageStyle, self).delete(mutagen_file)
        else:
            self.set(mutagen_file, None)


class MP3ImageStorageStyle(ListStorageStyle, MP3StorageStyle):
    """Converts between APIC frames and ``Image`` instances.

    The `get_list` method inherited from ``ListStorageStyle`` returns a
    list of ``Image``s. Similarly, the `set_list` method accepts a
    list of ``Image``s as its ``values`` argument.
    """
    def __init__(self):
        super(MP3ImageStorageStyle, self).__init__(key='APIC')
        self.as_type = bytes

    def deserialize(self, apic_frame):
        """Convert APIC frame into Image."""
        return Image(data=apic_frame.data, desc=apic_frame.desc,
                     type=apic_frame.type)

    def fetch(self, mutagen_file):

data = self.fetch(mutagen_file)
        if data is not None:
            return _sc_decode(data)[self.index]

    def set(self, mutagen_file, value):
        data = self.fetch(mutagen_file)
        if data is None:
            gain_peak = [0, 0]
        else:
            gain_peak = list(_sc_decode(data))
        gain_peak[self.index] = value or 0
        data = self.serialize(_sc_encode(*gain_peak))
        self.store(mutagen_file, data)


class ASFStorageStyle(ListStorageStyle):
    """A general storage style for Windows Media/ASF files.
    """
    formats = ['ASF']

    def deserialize(self, data):
        if isinstance(data, mutagen.asf.ASFBaseAttribute):
            data = data.value
        return data


class MP4StorageStyle(StorageStyle):
    """A general storage style for MPEG-4 tags.
    """
    formats = ['MP4']

    def serialize(self, value):

frame.encoding = mutagen.id3.Encoding.UTF16
        else:
            frame.encoding = mutagen.id3.Encoding.LATIN1

        frame.type = image.type_index
        return frame


class MP3SoundCheckStorageStyle(SoundCheckStorageStyleMixin,
                                MP3DescStorageStyle):
    def __init__(self, index=0, **kwargs):
        super(MP3SoundCheckStorageStyle, self).__init__(**kwargs)
        self.index = index


class ASFImageStorageStyle(ListStorageStyle):
    """Store images packed into Windows Media/ASF byte array attributes.
    Values are `Image` objects.
    """
    formats = ['ASF']

    def __init__(self):
        super(ASFImageStorageStyle, self).__init__(key='WM/Picture')

    def deserialize(self, asf_picture):
        mime, data, type, desc = _unpack_asf_image(asf_picture.value)
        return Image(data, desc=desc, type=type)

    def serialize(self, image):
        pic = mutagen.asf.ASFByteArrayAttribute()
        pic.value = _pack_asf_image(image.mime_type, image.data,
                                    type=image.type_index,

artist = MediaField(
        MP3StorageStyle('TPE1'),
        MP4StorageStyle('\xa9ART'),
        StorageStyle('ARTIST'),
        ASFStorageStyle('Author'),
    )
    album = MediaField(
        MP3StorageStyle('TALB'),
        MP4StorageStyle('\xa9alb'),
        StorageStyle('ALBUM'),
        ASFStorageStyle('WM/AlbumTitle'),
    )
    genres = ListMediaField(
        MP3ListStorageStyle('TCON'),
        MP4ListStorageStyle('\xa9gen'),
        ListStorageStyle('GENRE'),
        ASFStorageStyle('WM/Genre'),
    )
    genre = genres.single_field()

    lyricist = MediaField(
        MP3StorageStyle('TEXT'),
        MP4StorageStyle('----:com.apple.iTunes:LYRICIST'),
        StorageStyle('LYRICIST'),
        ASFStorageStyle('WM/Writer'),
    )
    composer = MediaField(
        MP3StorageStyle('TCOM'),
        MP4StorageStyle('\xa9wrt'),
        StorageStyle('COMPOSER'),
        ASFStorageStyle('WM/Composer'),
    )

"""Turn a Image into a mutagen.flac.Picture.
        """
        pic = mutagen.flac.Picture()
        pic.data = image.data
        pic.type = image.type_index
        pic.mime = image.mime_type
        pic.desc = image.desc or u''
        return pic

    def delete(self, mutagen_file):
        """Remove all images from the file.
        """
        mutagen_file.clear_pictures()


class APEv2ImageStorageStyle(ListStorageStyle):
    """Store images in APEv2 tags. Values are `Image` objects.
    """
    formats = ['APEv2File', 'WavPack', 'Musepack', 'MonkeysAudio', 'OptimFROG']

    TAG_NAMES = {
        ImageType.other: 'Cover Art (other)',
        ImageType.icon: 'Cover Art (icon)',
        ImageType.other_icon: 'Cover Art (other icon)',
        ImageType.front: 'Cover Art (front)',
        ImageType.back: 'Cover Art (back)',
        ImageType.leaflet: 'Cover Art (leaflet)',
        ImageType.media: 'Cover Art (media)',
        ImageType.lead_artist: 'Cover Art (lead)',
        ImageType.artist: 'Cover Art (artist)',
        ImageType.conductor: 'Cover Art (conductor)',
        ImageType.group: 'Cover Art (band)',

def serialize(self, image):
        """Turn a Image into a base64 encoded FLAC picture block.
        """
        pic = mutagen.flac.Picture()
        pic.data = image.data
        pic.type = image.type_index
        pic.mime = image.mime_type
        pic.desc = image.desc or u''

        # Encoding with base64 returns bytes on both Python 2 and 3.
        # Mutagen requires the data to be a Unicode string, so we decode
        # it before passing it along.
        return base64.b64encode(pic.write()).decode('ascii')


class FlacImageStorageStyle(ListStorageStyle):
    """Converts between ``mutagen.flac.Picture`` and ``Image`` instances.
    """
    formats = ['FLAC']

    def __init__(self):
        super(FlacImageStorageStyle, self).__init__(key='')

    def fetch(self, mutagen_file):
        return mutagen_file.pictures

    def deserialize(self, flac_picture):
        return Image(data=flac_picture.data, desc=flac_picture.desc,
                     type=flac_picture.type)

    def store(self, mutagen_file, pictures):
        """``pictures`` is a list of mutagen.flac.Picture instances.

def __init__(self):
        super(ASFImageStorageStyle, self).__init__(key='WM/Picture')

    def deserialize(self, asf_picture):
        mime, data, type, desc = _unpack_asf_image(asf_picture.value)
        return Image(data, desc=desc, type=type)

    def serialize(self, image):
        pic = mutagen.asf.ASFByteArrayAttribute()
        pic.value = _pack_asf_image(image.mime_type, image.data,
                                    type=image.type_index,
                                    description=image.desc or u'')
        return pic


class VorbisImageStorageStyle(ListStorageStyle):
    """Store images in Vorbis comments. Both legacy COVERART fields and
    modern METADATA_BLOCK_PICTURE tags are supported. Data is
    base64-encoded. Values are `Image` objects.
    """
    formats = ['OggOpus', 'OggTheora', 'OggSpeex', 'OggVorbis',
               'OggFlac']

    def __init__(self):
        super(VorbisImageStorageStyle, self).__init__(
            key='metadata_block_picture'
        )
        self.as_type = bytes

    def fetch(self, mutagen_file):
        images = []
        if 'metadata_block_picture' not in mutagen_file:

def set(self, mutagen_file, value):
        if value is None:
            value = 0
        items = self.deserialize(self.fetch(mutagen_file))
        items[self.index] = int(value)
        self.store(mutagen_file, items)

    def delete(self, mutagen_file):
        if self.index == 0:
            super(MP4TupleStorageStyle, self).delete(mutagen_file)
        else:
            self.set(mutagen_file, None)


class MP4ListStorageStyle(ListStorageStyle, MP4StorageStyle):
    pass


class MP4SoundCheckStorageStyle(SoundCheckStorageStyleMixin, MP4StorageStyle):
    def __init__(self, key, index=0, **kwargs):
        super(MP4SoundCheckStorageStyle, self).__init__(key, **kwargs)
        self.index = index


class MP4BoolStorageStyle(MP4StorageStyle):
    """A style for booleans in MPEG-4 files. (MPEG-4 has an atom type
    specifically for representing booleans.)
    """
    def get(self, mutagen_file):
        try:
            return mutagen_file[self.key]

encoding=mutagen.id3.Encoding.UTF8,
                people=[[self.involvement, value]]
            )
            mutagen_file.tags.add(frame)

    def fetch(self, mutagen_file):
        for frame in mutagen_file.tags.getall(self.key):
            for pair in frame.people:
                if pair[0].lower() == self.involvement.lower():
                    try:
                        return pair[1]
                    except IndexError:
                        return None


class MP3ListStorageStyle(ListStorageStyle, MP3StorageStyle):
    """Store lists of data in multiple ID3 frames.
    """
    def fetch(self, mutagen_file):
        try:
            return mutagen_file[self.key].text
        except KeyError:
            return []

    def store(self, mutagen_file, values):
        frame = mutagen.id3.Frames[self.key](encoding=3, text=values)
        mutagen_file.tags.setall(self.key, [frame])


class MP3UFIDStorageStyle(MP3StorageStyle):
    """Store string data in a UFID ID3 frame with a particular owner.
    """