How to use the mediafile.FileTypeError function in mediafile

def test_invalid_extension_raises_filetypeerror(self):
        self._exccheck(b'something.unknown', mediafile.FileTypeError)

elif type(self.mgfile).__name__ == 'FLAC':
            self.type = 'flac'
        elif type(self.mgfile).__name__ == 'OggOpus':
            self.type = 'opus'
        elif type(self.mgfile).__name__ == 'OggVorbis':
            self.type = 'ogg'
        elif type(self.mgfile).__name__ == 'MonkeysAudio':
            self.type = 'ape'
        elif type(self.mgfile).__name__ == 'WavPack':
            self.type = 'wv'
        elif type(self.mgfile).__name__ == 'Musepack':
            self.type = 'mpc'
        elif type(self.mgfile).__name__ == 'ASF':
            self.type = 'asf'
        else:
            raise FileTypeError('file type %s unsupported by MediaFile' %
                                type(self.mgfile).__name__)

        # add a set of tags if it's missing
        if self.mgfile.tags is None:
            self.mgfile.add_tags()

elif type(self.mgfile).__name__ == 'OggVorbis':
            self.type = 'ogg'
        elif type(self.mgfile).__name__ == 'MonkeysAudio':
            self.type = 'ape'
        elif type(self.mgfile).__name__ == 'WavPack':
            self.type = 'wv'
        elif type(self.mgfile).__name__ == 'Musepack':
            self.type = 'mpc'
        elif type(self.mgfile).__name__ == 'ASF':
            self.type = 'asf'
        elif type(self.mgfile).__name__ == 'AIFF':
            self.type = 'aiff'
        elif type(self.mgfile).__name__ == 'DSF':
            self.type = 'dsf'
        else:
            raise FileTypeError(path, type(self.mgfile).__name__)

        # Add a set of tags if it's missing.
        if self.mgfile.tags is None:
            self.mgfile.add_tags()

        # Set the ID3v2.3 flag only for MP3s.
        self.id3v23 = id3v23 and self.type == 'mp3'

def __init__(self, path, id3v23=False):
        """Constructs a new `MediaFile` reflecting the file at path. May
        throw `UnreadableFileError`.

        By default, MP3 files are saved with ID3v2.4 tags. You can use
        the older ID3v2.3 standard by specifying the `id3v23` option.
        """
        self.path = path

        self.mgfile = mutagen_call('open', path, mutagen.File, path)

        if self.mgfile is None:
            # Mutagen couldn't guess the type
            raise FileTypeError(path)
        elif type(self.mgfile).__name__ in ['M4A', 'MP4']:
            info = self.mgfile.info
            if info.codec and info.codec.startswith('alac'):
                self.type = 'alac'
            else:
                self.type = 'aac'
        elif type(self.mgfile).__name__ in ['ID3', 'MP3']:
            self.type = 'mp3'
        elif type(self.mgfile).__name__ == 'FLAC':
            self.type = 'flac'
        elif type(self.mgfile).__name__ == 'OggOpus':
            self.type = 'opus'
        elif type(self.mgfile).__name__ == 'OggVorbis':
            self.type = 'ogg'
        elif type(self.mgfile).__name__ == 'MonkeysAudio':
            self.type = 'ape'

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')
        elif type(self.mgfile).__name__ == 'M4A' or \
             type(self.mgfile).__name__ == 'MP4':
            # This hack differentiates AAC and ALAC until we find a more
            # deterministic approach. Mutagen only sets the sample rate
            # for AAC files. See:
            # https://github.com/sampsyo/beets/pull/295
            if hasattr(self.mgfile.info, 'sample_rate') and \
               self.mgfile.info.sample_rate > 0:
                self.type = 'aac'
            else:
                self.type = 'alac'
        elif type(self.mgfile).__name__ == 'ID3' or \
             type(self.mgfile).__name__ == 'MP3':
            self.type = 'mp3'
        elif type(self.mgfile).__name__ == 'FLAC':
            self.type = 'flac'