code: def _generate_examples(self, source_file, target_file):
      
      with tf.io.gfile.GFile(source_file) as f:
        source_sentences = f.read().split("\n")
      with tf.io.gfile.GFile(target_file) as f:
        target_sentences = f.read().split("\n")
  
      assert len(target_sentences) == len(
          source_sentences), "Sizes do not match: %d vs %d for %s vs %s." % (len(
              source_sentences), len(target_sentences), source_file, target_file)
  
      source, target = self.builder_config.language_pair
      for l1, l2 in zip(source_sentences, target_sentences):
        result = {source: l1, target: l2}
        # Make sure that both translations are non-empty.
        if all(result.values()):
          yield result
docs: This function returns the examples in the raw (text) form.