code: def _unexpected_mode(self):
      raise ValueError(
          'unexpected combine value (must be "mean" or "concat")'
      )
  
file_path: lightwood/lightwood/encoder/text/short.py
imports: from typing import List
  import torch
  from lightwood.encoder import BaseEncoder
  from lightwood.encoder.categorical import CategoricalAutoEncoder
  from type_infer.rule_based.helpers import tokenize_text
  from lightwood.helpers.torch import concat_vectors_and_pad, average_vectors
  import pandas
label_desc: Use image node_id 2 for calling the ShortTextEncoder obj's underlying member method code with example usage: obj._unexpected_mode() without return types