code: def describe(self):
          
          all_labels = []
          for f in self.active_features:
              all_labels += f.describe()
          return all_labels
docs: Returns a list of strings, one for each feature selected,
          with human-readable descriptions of the features.
  
          Returns
          -------
          labels : list of str
              An ordered list of strings, one for each feature selected,
              with human-readable descriptions of the features.