sub is_la_rare { 
    my $elt = shift; # can be <labels> or <def>
    foreach my $label ($elt->children('la') ) {
        next unless $label->text eq "rare";
        my $isNowRare = 0;
        if (
            ($label->att('fq') eq "0")
            || ($label->att('fq') eq "1")
            )
                { $isNowRare = 1; }
        if ( !$isNowRare ) { return 1; }
    }
    return 0;
}