142                                 entities=entities)

   142                                 entities=entities)

   143 

   143 

   144     def children_rql(self):

   144     def children_rql(self):

   145         return self.related_rql(self.tree_attribute, self.children_target)

   145         return self.related_rql(self.tree_attribute, self.children_target)

   146 

   146 

   150     def is_leaf(self):

   147     def is_leaf(self):

   151         return len(self.children()) == 0

   148         return len(self.children()) == 0

   152 

   149 

   153     def is_root(self):

   150     def is_root(self):

   154         return self.parent() is None

   151         return self.parent() is None