# checks if date is valid
sub validate {
    use Time::localtime;
    use Time::Local qw(timelocal_nocheck);

    my $day = $shift;
    my $month = $shift;
    my $year = $shift;

    my $local;
    eval {
        $local =
     localtime(timelocal_nocheck(0, 0, 0, $day, $month - 1, $year));
    };
    if($@) {
        if($@ =~ /^Can't handle date/) {
            return 0;
        } else {
            die $@;
        }
    }
    my $c_day = $local->mday;
    my $c_month = $local->mon + 1;
    my $c_year = $local->year + 1900;
    return($day == $c_day and $month == $c_month and $year == $c_year);
}