code: def _add_to_index_operations(self, which, reconstrained, what, warning):
          
          if warning and reconstrained.size > 0:
              # TODO: figure out which parameters have changed and only print those
              logging.getLogger(self.name).warning("reconstraining parameters {}".format(self.hierarchy_name() or self.name))
          index = self._raveled_index()
          which.add(what, index)
          return index
docs: Helper preventing copy code.
          This adds the given what (transformation, prior etc) to parameter index operations which.
          reconstrained are reconstrained indices.
          warn when reconstraining parameters if warning is True.
          TODO: find out which parameters have changed specifically