code: def _get_flat_path(path_pb):
      
      num_elts = len(path_pb.element)
      last_index = num_elts - 1
  
      result = []
      for index, element in enumerate(path_pb.element):
          result.append(element.type)
          _add_id_or_name(result, element, index == last_index)
  
      return tuple(result)
docs: Convert a legacy "Path" protobuf to a flat path.
  
      For example
  
          Element {
            type: "parent"
            id: 59
          }
          Element {
            type: "child"
            name: "naem"
          }
  
      would convert to ``('parent', 59, 'child', 'naem')``.
  
      :type path_pb: :class:`._app_engine_key_pb2.Path`
      :param path_pb: Legacy protobuf "Path" object (from a "Reference").
  
      :rtype: tuple
      :returns: The path parts from ``path_pb``.