code: def get_pipeline_alternatives(self, quiet=0):
          
          if not os.path.exists(self.BIDS_dir + '/derivatives/'):
              print('Derivative directory not found. Is the data preprocessed?')
          else:
              pipeline_alternatives = os.listdir(self.BIDS_dir + '/derivatives/')
              if quiet == 0:
                  print('Derivative alternatives: ' +
                        ', '.join(pipeline_alternatives))
              return list(pipeline_alternatives)
docs: The pipeline are the different outputs that are placed in the ./derivatives directory.
  
          get_pipeline_alternatives gets those which are found in the specified BIDS directory structure.