aclass.pm:

package aclass;
use strict;

sub new {
    my $self = {};
    $self->{"first"} = shift;
    $self->{"second"} = shift;
    bless $self;
    return $self;
}

1;

a.pl:
use aclass;
use strict;

sub display {
    my $a = shift;
    my $b = shift;
    print "a = $a, b = $b\n";
}

$a = new aclass(1, 2);
$b = new aclass(3, 4);
display($a, $b);
display(%{$a}, %{$b});