code: def feature_subset(self, indices):
          
          if isinstance(indices, np.ndarray):
              indices = indices.tolist()
          if not isinstance(indices, list):
              raise ValueError('Can only index with lists')
          return [self.features_[i] for i in indices]
docs: Returns some subset of the features.
          
          Parameters
          ----------
          indices : :obj:`list` of :obj:`int`
              indices of the features in the list
  
          Returns
          -------
          :obj:`list` of :obj:`Feature`