class_docstr: A Keras callback to save the model weights at the best epoch.
  
  Args:
      objective: An `Objective` instance.
      filepath: String. The file path to save the model weights.
class_docstr_tok: ["A","Keras","callback","to","save","the","model","weights","at","the","best","epoch",".","Args",":","objective",":","An","`","Objective","`","instance",".","filepath",":","String",".","The","file","path","to","save","the","model","weights","."]
code: def _save_model(self):
      if config.backend() != "tensorflow":
          self.model.save_weights(self.filepath)
          return
      # Create temporary saved model files on non-chief workers.
      write_filepath = backend.io.write_filepath(
          self.filepath, self.model.distribute_strategy
      )
      self.model.save_weights(write_filepath)
      # Remove temporary saved model files on non-chief workers.
      backend.io.remove_temp_dir_with_filepath(
          write_filepath, self.model.distribute_strategy
      )
  
imports: import collections
  import statistics
  import numpy
  from keras_tuner import backend
  from keras_tuner import errors
  from keras_tuner.backend import config
  from keras_tuner.backend import keras
  from keras_tuner.engine import hyperparameters
  from keras_tuner.engine import objective
label_desc: Use image node_id 3 for calling the SaveBestEpoch obj's underlying member method code with example usage: obj._save_model() without return types