docstr: Evaluate model.
  
  :param data: evaluation data.
  :param batch_size: batch size per thread.
  :return: evaluation result as a dictionary of {'metric name': metric value}
code: def evaluate(self, data, batch_size):
      """
      Evaluate model.
  
      :param data: evaluation data.
      :param batch_size: batch size per thread.
      :return: evaluation result as a dictionary of {'metric name': metric value}
      """
      raise NotImplementedError
  
file_path: analytics-zoo/pyzoo/zoo/orca/learn/base_estimator.py
imports: from abc import ABC, abstractmethod
label_desc: Use image node_id 3 for calling the BaseEstimator obj's underlying member method code with example usage: obj.evaluate(data, batch_size) without return types