use strict;
use warnings;
use Data::Dumper;

my $obj = MyTest->new();

#$obj->param('test', 555); #works fine
#$obj->param('test2', 55522); #works fine

$obj->param('test') = 555; 
$obj->param('test2') = 55522; 

my @params = $obj->param();
print Dumper(@params);

package MyTest;
sub new { bless { 'session' => {} }, shift; }
sub param {
	my $self = shift;
	my $name = shift;
	my @val = @_;
	$self->{session}->{$name} = $val[0] if @_;
	unless(@val) {
		return keys %{$self->{session}} unless $name;
		return $self->{session}->{$name};
	}
}

1;