beets: lyrics: If none are found, it exits with `AttributeError: 'NoneType' object has no attribute 'artist'

Problem

I search manually for lyrics of a specific track and It exits with the following traceback:

$ beet -vv lyrics artie shaw carioca
user configuration: /home/doron/.config/beets/config.yaml
data directory: /home/doron/.config/beets
plugin paths:
Sending event: pluginload
inline: adding item field isMultiDisc
library database: /var/lib/beets/db
library directory: /var/lib/mpd/music
Sending event: library_opened
lyrics: failed to fetch: https://www.musixmatch.com/lyrics/Artie-Shaw-and-His-Orchestra/Carioca (404)
lyrics: failed to fetch: https://www.musixmatch.com/lyrics/Artie-Shaw/Carioca (404)
lyrics: failed to fetch: https://www.musixmatch.com/es/letras/Buddy-Rich-Artie-Shaw/The-Carioca (404)
lyrics: failed to fetch: https://www.musixmatch.com/lyrics/Artie-Shaw/Carioca (404)
lyrics: lyrics not found: FLAC % Artie Shaw - Begin the Beguine | CD-04 | 25 Carioca
Traceback (most recent call last):
  File "/usr/bin/beet", line 11, in <module>
    load_entry_point('beets==1.4.6', 'console_scripts', 'beet')()
  File "/usr/lib/python3.6/site-packages/beets/ui/__init__.py", line 1256, in main
    _raw_main(args)
  File "/usr/lib/python3.6/site-packages/beets/ui/__init__.py", line 1243, in _raw_main
    subcommand.func(lib, suboptions, subargs)
  File "/usr/lib/python3.6/site-packages/beetsplug/lyrics.py", line 734, in func
    self.writerest(opts.writerest, None)
  File "/usr/lib/python3.6/site-packages/beetsplug/lyrics.py", line 762, in writerest
    self.artist = item.artist.strip()
AttributeError: 'NoneType' object has no attribute 'artist'

Setup

$ uname -ors
Linux 4.14.15-1-ARCH GNU/Linux

• Python version: 3.6.4
• beets version: 1.4.6
• Turning off plugins made problem go away (yes/no): lyrics plugin of course.

My configuration (output of beet config) is:

lyrics:
    bing_lang_from: []
    google_API_key: REDACTED
    sources: google musixmatch
    auto: yes
    bing_client_secret: REDACTED
    bing_lang_to:
    google_engine_ID: REDACTED
    genius_api_key: REDACTED
    fallback:
    force: no
    local: no

musicbrainz:
    pass: REDACTED
    host: musicbrainz.org
    ratelimit: 1
    ratelimit_interval: 1.0
    searchlimit: 10
    user: doronbehar
acoustid:
    apikey: REDACTED
mpd:
    host: localhost
    port: 6600
    password: REDACTED
    music_directory: /var/lib/mpd/music
    rating: yes
    rating_mix: 0.75
library: /var/lib/beets/db
directory: /var/lib/mpd/music

import:
    write: yes
    copy: yes
    move: no
    link: no
    delete: no
    resume: ask
    incremental: no
    quiet_fallback: skip
    none_rec_action: ask
    timid: no
    log: ~/.local/share/beets/log
    autotag: yes
    quiet: no
    singletons: no
    default_action: apply
    languages: []
    detail: no
    flat: no
    group_albums: no
    pretend: no
    search_ids: []
    duplicate_action: ask

clutter: [Thumbs.DB, .DS_Store]
ignore:
- .*
- '*~'
- System Volume Information
- lost+found
ignore_hidden: yes

replace:
    '[\\/]': '-'
    ^\.: _
    '[\x00-\x1f]': _
    '[<>"\?\*\|]': _
    ':': ' -'
    \s+$: ''
    ^\s+: ''
path_sep_replace: _
asciify_paths: no
art_filename: cover
max_filename_length: 0

plugins:
- absubmit
- acousticbrainz
- inline
- mbcollection
- chroma
- fromfilename
- info
- duplicates
- edit
- fetchart
- ipfs
- lastgenre
- missing
- mbsync
- mpdstats
- mpdupdate
- lyrics
pluginpath: []
threaded: yes
timeout: 5.0
per_disc_numbering: yes
verbose: 0
terminal_encoding:
original_date: no
id3v23: no
va_name: Various Artists

ui:
    terminal_width: 80
    length_diff_thresh: 10.0
    color: yes
    colors:
        text_success: green
        text_warning: yellow
        text_error: red
        text_highlight: red
        text_highlight_minor: lightgray
        action_default: turquoise
        action: blue

format_item: ${format} % ${albumartist} - ${album} | CD-${disc} | ${track} ${title}
format_album: $album
time_format: '%Y-%m-%d %H:%M:%S'
format_raw_length: no

sort_album: albumartist+ album+
sort_item: artist+ album+ disc+ track+
sort_case_insensitive: yes
item_fields:
    isMultiDisc: "u'yes' if\n    (int(disctotal) > 1) and (disctotal != '')\nelse\n    u''\n"

paths:
    default: $album%aunique{album, albumartist}/%if{$isMultiDisc,CD-$disc/}$track $title
    singleton: $artist - Singles/$title
    comp: $album%aunique{album, albumartist}/%if{$isMultiDisc,CD-$disc/}$track $title

statefile: ~/.cache/beets/state.pickle
chrome:
    auto: no
ipfs:
    auto: no
lastgenre:
    force: no
    source: track
    whitelist: yes
    min_weight: 10
    count: 1
    fallback:
    canonical: no
    auto: yes
    separator: ', '
    prefer_specific: no

match:
    strong_rec_thresh: 0.04
    medium_rec_thresh: 0.25
    rec_gap_thresh: 0.25
    max_rec:
        missing_tracks: medium
        unmatched_tracks: medium
    distance_weights:
        source: 2.0
        artist: 3.0
        album: 3.0
        media: 1.0
        mediums: 1.0
        year: 1.0
        country: 0.5
        label: 0.5
        catalognum: 0.5
        albumdisambig: 0.5
        album_id: 5.0
        tracks: 2.0
        missing_tracks: 0.9
        unmatched_tracks: 0.6
        track_title: 3.0
        track_artist: 2.0
        track_index: 1.0
        track_length: 2.0
        track_id: 5.0
    preferred:
        countries: []
        media: []
        original_year: no
    ignored: []
    required: []
    track_length_grace: 10
    track_length_max: 30
absubmit:
    auto: yes
    extractor: ''
include: [passwords.yaml]
edit:
    albumfields: album albumartist
    itemfields: track title artist album
    ignore_fields: id path
duplicates:
    album: no
    checksum: ''
    copy: ''
    count: no
    delete: no
    format: ''
    full: no
    keys: []
    merge: no
    move: ''
    path: no
    tiebreak: {}
    strict: no
    tag: ''
acousticbrainz:
    auto: yes
    force: no
    tags: []
chroma:
    auto: yes
missing:
    count: no
    total: no
    album: no
pathfields: {}
album_fields: {}
fetchart:
    auto: yes
    minwidth: 0
    maxwidth: 0
    enforce_ratio: no
    cautious: no
    cover_names:
    - cover
    - front
    - art
    - album
    - folder
    sources:
    - filesystem
    - coverart
    - itunes
    - amazon
    - albumart
    google_key: REDACTED
    google_engine: 001442825323518660753:hrh5ch1gjzm
    fanarttv_key: REDACTED
    store_source: no
mbcollection:
    auto: no
    collection: ''
    remove: no