code: def postprocess(self, x, **kwargs):
      if self._postprocess_fn is None:
          raise UserWarning("postprocess method not defined")
      return self._postprocess_fn(x, **kwargs)
  
file_path: chitra/chitra/data_processing/processor.py
imports: from typing import Callable, Optional
label_desc: Use image node_id 7 for calling the DataProcessor obj's underlying member method code with example usage: obj.postprocess(x) and returns: self