How to use the beets.ui.print_ function in beets

`item` must be provided.

    Returns the result of the choice, which may SKIP, ASIS, TRACKS, or
    MANUAL or a candidate (an AlbumMatch/TrackMatch object).
    """
    # Sanity check.
    if singleton:
        assert item is not None
    else:
        assert cur_artist is not None
        assert cur_album is not None

    # Zero candidates.
    if not candidates:
        if singleton:
            print_("No matching recordings found.")
            opts = ('Use as-is', 'Skip', 'Enter search', 'enter Id',
                    'aBort')
        else:
            print_("No matching release found for {0} tracks."
                   .format(itemcount))
            print_('For help, see: '
                   'http://beets.readthedocs.org/en/latest/faq.html#nomatch')
            opts = ('Use as-is', 'as Tracks', 'Group albums', 'Skip',
                    'Enter search', 'enter Id', 'aBort')
        sel = ui.input_options(opts)
        if sel == 'u':
            return importer.action.ASIS
        elif sel == 't':
            assert not singleton
            return importer.action.TRACKS
        elif sel == 'e':

if match.info.data_url:
        print_(u'URL:\n    %s' % match.info.data_url)

    # Info line.
    info = []
    # Similarity.
    info.append(u'(Similarity: %s)' % dist_string(match.distance))
    # Penalties.
    penalties = penalty_string(match.distance)
    if penalties:
        info.append(penalties)
    # Disambiguation.
    disambig = disambig_string(match.info)
    if disambig:
        info.append(ui.colorize('text_highlight_minor', u'(%s)' % disambig))
    print_(' '.join(info))

    # Tracks.
    pairs = match.mapping.items()
    pairs.sort(key=lambda item_and_track_info: item_and_track_info[1].index)

    # Build up LHS and RHS for track difference display. The `lines` list
    # contains ``(lhs, rhs, width)`` tuples where `width` is the length (in
    # characters) of the uncolorized LHS.
    lines = []
    medium = disctitle = None
    for item, track_info in pairs:

        # Medium number and title.
        if medium != track_info.medium or disctitle != track_info.disctitle:
            media = match.info.media or 'Media'
            if match.info.mediums > 1 and track_info.disctitle:

if not rhs:
                print_(lhs)
            elif max_width > col_width:
                print_(u'%s ->\n   %s' % (lhs, rhs))
            else:
                pad = max_width - lhs_width
                print_(u'%s%s -> %s' % (lhs, ' ' * pad, rhs))

    # Missing and unmatched tracks.
    if match.extra_tracks:
        print_('Missing tracks:')
    for track_info in match.extra_tracks:
        line = ' ! %s (#%s)' % (track_info.title, format_index(track_info))
        if track_info.length:
            line += ' (%s)' % ui.human_seconds_short(track_info.length)
        print_(ui.colorize('yellow', line))
    if match.extra_items:
        print_('Unmatched tracks:')
    for item in match.extra_items:
        line = ' ! %s (#%s)' % (item.title, format_index(item))
        if item.length:
            line += ' (%s)' % ui.human_seconds_short(item.length)
        print_(ui.colorize('yellow', line))

if opts.album:
                fmt = cl + cl.join(['$albumartist', '$album'])
            else:
                fmt = cl + cl.join(['$title', '$artist'])
        else:
            for it in self.fields:
                if opts.album:
                    if it not in library.Album.all_keys():
                        print_(
                            "{} not in albumfields.Removed it.".format(
                                ui.colorize(
                                    'text_warning', it)))
                        self.fields.remove(it)
                else:
                    if it not in library.Item.all_keys():
                        print_(
                            "{} not in itemfields.Removed it.".format(
                                ui.colorize(
                                    'text_warning', it)))
                        self.fields.remove(it)
            self.pick = "selected"
            fmtfields = ["$" + it for it in self.fields]
            fmt = cl + cl.join(fmtfields[1:])

        return fmt

if match.info.data_url:
        print_(u'URL:\n    %s' % match.info.data_url)

    # Info line.
    info = []
    # Similarity.
    info.append(u'(Similarity: %s)' % dist_string(match.distance))
    # Penalties.
    penalties = penalty_string(match.distance)
    if penalties:
        info.append(penalties)
    # Disambiguation.
    disambig = disambig_string(match.info)
    if disambig:
        info.append(ui.colorize('text_highlight_minor', u'(%s)' % disambig))
    print_(' '.join(info))

if match.info.data_url:
        print_(u'URL:\n    %s' % match.info.data_url)

    # Info line.
    info = []
    # Similarity.
    info.append(u'(Similarity: %s)' % dist_string(match.distance))
    # Penalties.
    penalties = penalty_string(match.distance)
    if penalties:
        info.append(penalties)
    # Disambiguation.
    disambig = disambig_string(match.info)
    if disambig:
        info.append(ui.colorize('text_highlight_minor', u'(%s)' % disambig))
    print_(' '.join(info))

    # Tracks.
    pairs = list(match.mapping.items())
    pairs.sort(key=lambda item_and_track_info: item_and_track_info[1].index)

    # Build up LHS and RHS for track difference display. The `lines` list
    # contains ``(lhs, rhs, width)`` tuples where `width` is the length (in
    # characters) of the uncolorized LHS.
    lines = []
    medium = disctitle = None
    for item, track_info in pairs:

        # Medium number and title.
        if medium != track_info.medium or disctitle != track_info.disctitle:
            media = match.info.media or 'Media'
            if match.info.mediums > 1 and track_info.disctitle:

def fields_func(lib, opts, args):
    def _print_rows(names):
        names.sort()
        print_("  " + "\n  ".join(names))

    print_(u"Item fields:")
    _print_rows(library.Item.all_keys())

    print_(u"Album fields:")
    _print_rows(library.Album.all_keys())

    with lib.transaction() as tx:
        # The SQL uses the DISTINCT to get unique values from the query
        unique_fields = 'SELECT DISTINCT key FROM (%s)'

        print_(u"Item flexible attributes:")
        _print_keys(tx.query(unique_fields % library.Item._flex_table))

        print_(u"Album flexible attributes:")
        _print_keys(tx.query(unique_fields % library.Album._flex_table))

def authenticate(self, c_key, c_secret):
        # Get the link for the OAuth page.
        auth_client = Client(USER_AGENT, c_key, c_secret)
        try:
            _, _, url = auth_client.get_authorize_url()
        except CONNECTION_ERRORS as e:
            self._log.debug(u'connection error: {0}', e)
            raise beets.ui.UserError(u'communication with Discogs failed')

        beets.ui.print_(u"To authenticate with Discogs, visit:")
        beets.ui.print_(url)

        # Ask for the code and validate it.
        code = beets.ui.input_(u"Enter the code:")
        try:
            token, secret = auth_client.get_access_token(code)
        except DiscogsAPIError:
            raise beets.ui.UserError(u'Discogs authorization failed')
        except CONNECTION_ERRORS as e:
            self._log.debug(u'connection error: {0}', e)
            raise beets.ui.UserError(u'Discogs token request failed')

        # Save the token for later use.
        self._log.debug(u'Discogs token {0}, secret {1}', token, secret)
        with open(self._tokenfile(), 'w') as f:
            json.dump({'token': token, 'secret': secret}, f)

items, albums = _do_query(lib, query, album, False)
    objs = albums if album else items

    # Apply changes *temporarily*, preview them, and collect modified
    # objects.
    print_('Modifying %i %ss.' % (len(objs), 'album' if album else 'item'))
    changed = set()
    for obj in objs:
        for field, value in fsets.iteritems():
            obj[field] = value
        if ui.show_model_changes(obj):
            changed.add(obj)

    # Still something to do?
    if not changed:
        print_('No changes to make.')
        return

    # Confirm action.
    if confirm:
        extra = ' and write tags' if write else ''
        if not ui.input_yn('Really modify%s (Y/n)?' % extra):
            return

    # Apply changes to database.
    with lib.transaction():
        for obj in changed:
            if move:
                cur_path = obj.path
                if lib.directory in ancestry(cur_path): # In library?
                    log.debug('moving object %s' % cur_path)
                    obj.move()

match = candidates[0]
        bypass_candidates = True

    while True:
        # Display and choose from candidates.
        require = rec <= Recommendation.low

        if not bypass_candidates:
            # Display list of candidates.
            print_(u'Finding tags for {0} "{1} - {2}".'.format(
                u'track' if singleton else u'album',
                item.artist if singleton else cur_artist,
                item.title if singleton else cur_album,
            ))

            print_(u'Candidates:')
            for i, match in enumerate(candidates):
                # Index, metadata, and distance.
                line = [
                    u'{0}.'.format(i + 1),
                    u'{0} - {1}'.format(
                        match.info.artist,
                        match.info.title if singleton else match.info.album,
                    ),
                    u'({0})'.format(dist_string(match.distance)),
                ]

                # Penalties.
                penalties = penalty_string(match.distance, 3)
                if penalties:
                    line.append(penalties)