return $new_group if Hash::Util::FieldHash::id($old_group) == Hash::Util::FieldHash::id($new_group);
# move to a new parent
$self->remove(signal => 0) if $old_group;
return $new_group if Hash::Util::FieldHash::id($old_group) == Hash::Util::FieldHash::id($new_group);
# move to a new parent
$self->remove(signal => 0) if $old_group;