code: def _get_optional_parameters(self):
      return {
          "past_seq_len",
          "latent_dim",
          "dropout",
          "metric",
          "lr",
          "epochs",
          "batch_size",
      }
  
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 18 for calling the LSTMSeq2Seq obj's underlying member method code with example usage: obj._get_optional_parameters() and returns: unknown