code: def _get_support_mask(self):
          
          check_is_fitted(self, 'feat_list_idx')
          n_features = len(self.feature_names)
          mask = np.zeros(n_features, dtype=bool)
          mask[np.asarray(self.feat_list_idx)] = True
  
          return mask
docs: Get the boolean mask indicating which features are selected
          Returns
          -------
          support : boolean array of shape [# input features]
              An element is True iff its corresponding feature is selected for
              retention.