package board;
...

use lib('.');
use hole;

#
# new - board constructor
#
# holes ) is an ref to a array of hole objects
#         This is not typically passed in to the
#         constructor.  The constructor will build
#         the holes attribute $holes is not passed.
#
# level ) is also not typically used.
#
sub new {
	my ($pkg, $holes, $level) = @_;

	unless ( $holes ) {
		#
		# create the holes
		#
                ...
	}
	my $obj = bless {
		holes	=> $holes, # ref to array of holes
		level	=> defined( $level ) ? $level : 0
	}, $pkg;
	return $obj;
}

sub getHoles {
	my $obj = shift;
	return wantarray ? @{$obj->{'holes'}} : $obj->{'holes'};
...
1;
}