push @lines, $prefix . '<a href="/music/empty2.opus">Opus</a> ' if $handled{'.opus'};
push @lines, $prefix . '<a href="/music/empty3.mp3">MP3</a> ' if $handled{'.mp3'};
push @lines, $prefix . '<a href="/music/empty2.opus">Opus</a> ' if $handled{'.opus'};
push @lines, $prefix . '<a href="/music/empty3.mp3">MP3</a> ' if $handled{'.mp3'};