code: def _get_optional_parameters(self):
      return {
          "hidden_dim",
          "layer_num",
          "dropout",
      } | super()._get_optional_parameters()
  
file_path: analytics-zoo/pyzoo/zoo/chronos/model/VanillaLSTM_pytorch.py
imports: import torch
  import torch.nn
  from zoo.orca.automl.model.base_pytorch_model import PytorchBaseModel
label_desc: Use image node_id 3 for calling the VanillaLSTMPytorch obj's underlying member method code with example usage: obj._get_optional_parameters() and returns: unknown