How to use the mediafile.UnreadableFileError function in mediafile

def test_corrupt_monkeys_raises_unreadablefileerror(self):
        self._exccheck(b'corrupt.ape', mediafile.UnreadableFileError)

def test_save_nonexisting(self):
        mediafile = self._mediafile_fixture('full')
        os.remove(mediafile.path)
        try:
            mediafile.save()
        except UnreadableFileError:
            pass

if id3v23 is None:
            id3v23 = beets.config['id3v23'].get(bool)

        # Get the data to write to the file.
        item_tags = dict(self)
        item_tags = {k: v for k, v in item_tags.items()
                     if k in self._media_fields}  # Only write media fields.
        if tags is not None:
            item_tags.update(tags)
        plugins.send('write', item=self, path=path, tags=item_tags)

        # Open the file.
        try:
            mediafile = MediaFile(syspath(path), id3v23=id3v23)
        except UnreadableFileError as exc:
            raise ReadError(path, exc)

        # Write the tags to the file.
        mediafile.update(item_tags)
        try:
            mediafile.save()
        except UnreadableFileError as exc:
            raise WriteError(self.path, exc)

        # The file has a new mtime.
        if path == self.path:
            self.mtime = self.current_mtime()
        plugins.send('after_write', item=self, path=path)

`action` is a string describing what the function is trying to do,
    and `path` is the relevant filename. The rest of the arguments
    describe the callable to invoke.

    We require at least Mutagen 1.33, where `IOError` is *never* used,
    neither for internal parsing errors *nor* for ordinary IO error
    conditions such as a bad filename. Mutagen-specific parsing errors and IO
    errors are reraised as `UnreadableFileError`. Other exceptions
    raised inside Mutagen---i.e., bugs---are reraised as `MutagenError`.
    """
    try:
        return func(*args, **kwargs)
    except mutagen.MutagenError as exc:
        log.debug(u'%s failed: %s', action, six.text_type(exc))
        raise UnreadableFileError(path, six.text_type(exc))
    except Exception as exc:
        # Isolate bugs in Mutagen.
        log.debug(u'%s', traceback.format_exc())
        log.error(u'uncaught Mutagen exception in %s: %s', action, exc)
        raise MutagenError(path, exc)

def _scrub_item(self, item, restore=True):
        """Remove tags from an Item's associated file and, if `restore`
        is enabled, write the database's tags back to the file.
        """
        # Get album art if we need to restore it.
        if restore:
            try:
                mf = mediafile.MediaFile(util.syspath(item.path),
                                         config['id3v23'].get(bool))
            except mediafile.UnreadableFileError as exc:
                self._log.error(u'could not open file to scrub: {0}',
                                exc)
                return
            images = mf.images

        # Remove all tags.
        self._scrub(item.path)

        # Restore tags, if enabled.
        if restore:
            self._log.debug(u'writing new tags after scrub')
            item.try_write()
            if images:
                self._log.debug(u'restoring art')
                try:
                    mf = mediafile.MediaFile(util.syspath(item.path),

__all__ = ['UnreadableFileError', 'FileTypeError', 'MediaFile']


# Logger.
log = logging.getLogger('beets')


# Exceptions.

# Raised for any file MediaFile can't read.
class UnreadableFileError(Exception):
    pass

# Raised for files that don't seem to have a type MediaFile supports.
class FileTypeError(UnreadableFileError):
    pass


# Constants.

# Human-readable type names.
TYPES = {
    'mp3':  'MP3',
    'aac':  'AAC',
    'alac':  'ALAC',
    'ogg':  'OGG',
    'opus': 'Opus',
    'flac': 'FLAC',
    'ape':  'APE',
    'wv':   'WavPack',
    'mpc':  'Musepack',

mutagen.mp3.error,
            mutagen.id3.error,
            mutagen.flac.error,
            mutagen.monkeysaudio.MonkeysAudioHeaderError,
            mutagen.mp4.error,
            mutagen.oggopus.error,
            mutagen.oggvorbis.error,
            mutagen.ogg.error,
            mutagen.asf.error,
            mutagen.apev2.error,
        )
        try:
            self.mgfile = mutagen.File(path)
        except unreadable_exc as exc:
            log.debug(u'header parsing failed: {0}'.format(unicode(exc)))
            raise UnreadableFileError('Mutagen could not read file')
        except IOError as exc:
            if type(exc) == IOError:
                # This is a base IOError, not a subclass from Mutagen or
                # anywhere else.
                raise
            else:
                log.debug(traceback.format_exc())
                raise UnreadableFileError('Mutagen raised an exception')
        except Exception as exc:
            # Hide bugs in Mutagen.
            log.debug(traceback.format_exc())
            log.error('uncaught Mutagen exception: {0}'.format(exc))
            raise UnreadableFileError('Mutagen raised an exception')

        if self.mgfile is None: # Mutagen couldn't guess the type
            raise FileTypeError('file type unsupported by Mutagen')

'dsf':  'DSD Stream File',
}

PREFERRED_IMAGE_EXTENSIONS = {'jpeg': 'jpg'}


# Exceptions.

class UnreadableFileError(Exception):
    """Mutagen is not able to extract information from the file.
    """
    def __init__(self, path, msg):
        Exception.__init__(self, msg if msg else repr(path))


class FileTypeError(UnreadableFileError):
    """Reading this type of file is not supported.

    If passed the `mutagen_type` argument this indicates that the
    mutagen type is not supported by `Mediafile`.
    """
    def __init__(self, path, mutagen_type=None):
        if mutagen_type is None:
            msg = u'{0!r}: not in a recognized format'.format(path)
        else:
            msg = u'{0}: of mutagen type {1}'.format(repr(path), mutagen_type)
        Exception.__init__(self, msg)


class MutagenError(UnreadableFileError):
    """Raised when Mutagen fails unexpectedly---probably due to a bug.
    """