sub employees {
    my $node = shift;
    my $val = shift;
    $node->attributes->{employees} = $val if $val;
    return $node->attributes->{employees};
}

sub budget {
    my $node = shift;
    my $val = shift;
    $node->attributes->{budget} = $val if $val;
    return $node->attributes->{budget};
}

sub by_name {
    my ($self, $name) = @_;
    my @found =();
    my $retvalue = wantarray ? 1 : 0;
    $self->walk_down({callback=>sub{
        if ($_[0]->name eq $name) {
            push @found, $_[0];
            return $retvalue;
        }
        1}});
    return wantarray? @found : @found ? $found[0] : undef;
}