code: def _describe_tree(self, prefix, with_transform):
          
          extra = ': "%s"' % self.name if self.name is not None else ''
          if with_transform:
              extra += (' [%s]' % self.transform.__class__.__name__)
          output = ''
          if len(prefix) > 0:
              output += prefix[:-3]
              output += '  +--'
          output += '%s%s\n' % (self.__class__.__name__, extra)
  
          n_children = len(self.children)
          for ii, child in enumerate(self.children):
              sub_prefix = prefix + ('   ' if ii+1 == n_children else '  |')
              output += child._describe_tree(sub_prefix, with_transform)
          return output
docs: Helper function to actuall construct the tree