code: def leaf_handler(self,*args):
          '''#leaf child handler'''
          desc = self.desc
          pdesc = self.pdesc
          desc['leaf'] = True
          desc['sons_count'] = 0
          pdesc['leaf_son_paths'].append(copy.deepcopy(desc['path']))
          pdesc['leaf_descendant_paths'].append(copy.deepcopy(desc['path'])f leaf_handler(self,*args):
          '''#leaf child handler'''
          desc = self.desc
          pdesc = self.pdesc
          desc['leaf'] = True
          desc['sons_count'] = 0
          pdesc['leaf_son_paths'].append(copy.deepcopy(desc['path']))
          pdesc['leaf_descendant_paths'].append(copy.deepcopy(desc['path']))
docs: #leaf child handler