my @cols;
my @row;
sub hash2csv {
        my $h = shift;
        my $p = shift || 'top';
        foreach my $k ( keys %{$h} ) {
                if (ref $h->{$k} eq ref {}) {
                        hash2csv( $h->{$k}, $k );
                } else {
                        if ( $p eq 'top' ) {
                                push @cols, $k;
                        } else {
                                push @cols, "$p.$k";
                        }
                        push @row, $h->{$k};
                }
        }
}