code: def __str__(self):
      return (
          "Dataset: %s with %i train examples, %i dev examples and %i test examples"
          % (
              self.__class__.__name__,
              len(self.train_examples),
              len(self.dev_examples),
              len(self.test_examples),
          )
      )
  
imports: import os
  from paddlehub.utils.log import logger
label_desc: Use image node_id 17 for calling the BaseDataset obj's underlying member method code with example usage: obj.__str__() and returns: unknown