docstr: save model to file.
  :param checkpoint_file: the model file path to be saved to.
  :param config_path: the config file path to be saved to.
  :return:
docstr_tok: ["save","model","to","file",".",":","param","checkpoint_file",":","the","model","file","path","to","be","saved","to",".",":","param","config_path",":","the","config","file","path","to","be","saved","to",".",":","return",":"]
code: def save(self, checkpoint_file, config_path=None):
      """
      save model to file.
      :param checkpoint_file: the model file path to be saved to.
      :param config_path: the config file path to be saved to.
      :return:
      """
      state_dict = self.state_dict()
      with open(checkpoint_file, "wb") as f:
          pickle.dump(state_dict, f)
  
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 15 for calling the LSTMSeq2Seq obj's underlying member method code with example usage: obj.save(checkpoint_file, config_path) without return types