$month ||= $self->month;
$year ||= $self->year;
my $date = DateCalc(sprintf("%04d%02d%02d", $year, $month, $day),
- "+ $delta days");
+ ($delta < 0 ? '':'+')." $delta days");
my($y, $m, $d) = $date =~ /^(\d{4})(\d\d)(\d\d)/;
$_ += 0 foreach ($y, $m, $d);
($d, $m, $y);