Perl计算日期时间间隔

#! /usr/bin/env perl

use DateTime;

my $dt_01 = DateTime->new(year=> 2015, month=> 5, day =>3);
my $dt_02 = DateTime->new(year=> 2015, month=> 5, day =>1);
my $du    = $dt_01->subtract_datetime_absolute($dt_02);

print $du->seconds();
print "\n";