def get_result_class(cls):
    """
    For the given model class, determine what class we should use for the
    nodes returned by its tree methods (such as get_children).

    Usually this will be trivially the same as the initial model class,
    but there are special cases when model inheritance is in use:

    * If the model extends another via multi-table inheritance, we need to
      use whichever ancestor originally implemented the tree behaviour (i.e.
      the one which defines the 'path' field). We can't use the
      subclass, because it's not guaranteed that the other nodes reachable
      from the current one will be instances of the same subclass.

    * If the model is a proxy model, the returned nodes should also use
      the proxy class.
    """
    base_class = cls._meta.get_field('path').model
    if cls._meta.proxy_for_model == base_class:
        return cls
    else:
        return base_class
