my $parent1 = Person->create({ name => 'P1' });
my $parent2 = Person->create({ name => 'P2' });

my $child = Person->create({ name => 'C1' });

# This seems like a cumbersome way to set up the relationships
$child->add_to_parents({ parent => $parent1 });
$child->add_to_parents({ parent => $parent2 });

# Or, alternatively
# $parent1->add_to_children({ child => $child });
# $parent2->add_to_children({ child => $child });