code: def get_sorted_pos_queryset(self, siblings, newobj):
          
  
          fields, filters = [], []
          for field in self.node_order_by:
              value = getattr(newobj, field)
              filters.append(
                  Q(
                      *[Q(**{f: v}) for f, v in fields] +
                       [Q(**{'%s__gt' % field: value})]
                  )
              )
              fields.append((field, value))
          return siblings.filter(reduce(operator.or_, filters))
docs: :returns: A queryset of the nodes that must be moved
          to the right. Called only for Node models with :attr:`node_order_by`
  
          This function is based on _insertion_target_filters from django-mptt
          (BSD licensed) by Jonathan Buchanan:
          https://github.com/django-mptt/django-mptt/blob/0.3.0/mptt/signals.py