sub new {
    my $class = shift;
    my %attrs = @_;
    
    my @products = ({
        'id'            => 0,
        'name'          => 'Test',
        'description'   => 'Some test data',
        'qty'           => 1,
        'price'         => 1000,
    });
    $attrs{'trolley'} = \@products;
    
    return bless \%attrs, $class;
}

##</code><code>##

sub add_product {
    my ($self, $product_data) = @_;
    # create $new_product hasfref
    push $self->{'trolley'}, $new_product;
    push @{$self->{'trolley'}}, $new_product;
}