package DateTime::Duration;

use strict;

use Params::Validate qw( validate SCALAR );

. . .

sub new
{
    my $class = shift;
    my %p = validate( @_, 
                         { years   => { type => SCALAR, default => 0 },
                           months  => { type => SCALAR, default => 0 },
                           weeks   => { type => SCALAR, default => 0 },
                           days    => { type => SCALAR, default => 0 },
                           hours   => { type => SCALAR, default => 0 },
                           minutes => { type => SCALAR, default => 0 },
                           seconds => { type => SCALAR, default => 0 },
                           end_of_month => { type => SCALAR, default => 'wrap' },
                         } );
. . .