sub keywords {
	my $self = shift;
	croak 'Not called as a method by parent object'
		unless ref $self && UNIVERSAL::isa($self, __PACKAGE__);

	my %keywords;
	my $stor = $objstore->{_refaddr($self)};
	for my $handle (@{$stor->{parsed}->{handles}}) {
		for my $keyword ($handle->keywords) {
			$keywords{$keyword} = 1;
		}
	}

	return sort(keys(%keywords));
}