code: def has_preprocessed(self):
      return hasattr(self, "_batch_transformed")
  
file_path: ray/python/ray/train/tests/dummy_preprocessor.py
imports: import uuid
  from ray.data.preprocessor import Preprocessor
label_desc: Use image node_id 4 for calling the DummyPreprocessor obj's underlying member method code with example usage: obj.has_preprocessed() and returns: hasattr