-sub _addparent
-{
- my $self = shift;
- return $self->_addlist('parent', @_);
-}
-
-sub _delparent
-{
- my $self = shift;
- return $self->_dellist('parent', @_);
-}
-
-
-sub _addnode
-{
- my $self = shift;
- return $self->_addlist('nodes', @_);
-}
-
-sub _delnode
-{
- my $self = shift;
- return $self->_dellist('nodes', @_);
-}
-