sub format_header($) {
    my ($header) = "X-Header";
    my ($value) = @_;

    $value =~ s/,/, /g; 

    use Mail::Header();
    my ($headers) = new Mail::Header (Modify => 1, FoldLength => 70);
    $headers->add($header, $value);
    $value = $headers->get($header);
    chop ($value);

    $value =~ s/, /,/g;
    $value =~ s/    /\t/g;

    return $value;
}