docstr: expand dims for y.
  :param y:
  :return:
docstr_tok: ["expand","dims","for","y.",":","param","y",":",":","return",":"]
code: def _expand_y(self, y):
      """
      expand dims for y.
      :param y:
      :return:
      """
      while len(y.shape) < 3:
          y = np.expand_dims(y, axis=2)
      return y
  
imports: import pickle
  import numpy
  from tensorflow.keras.models import Model
  from tensorflow.keras.layers import Input, LSTM, Dense
  import tensorflow.keras
  from zoo.orca.automl.model.abstract import BaseModel
  from zoo.orca.automl.metrics import Evaluator
label_desc: Use image node_id 8 for calling the LSTMSeq2Seq obj's underlying member method code with example usage: obj._expand_y(y) and returns: y