code: def istats(self, start=0, end=-1, fields=None):
          '''Perform a multivariate statistic calculation of this
  :class:`ColumnTS` from *start* to *end*.
  
  :param start: Optional index (rank) where to start the analysis.
  :param end: Optional index (rank) where to end the analysis.
  :param fields: Optional subset of :meth:`fields` to perform analysis on.
      If not provided all fields are included in the analysis.
  '''
          backend = self.read_backend
          return backend.execute(
              backend.structure(self).istats(start, end, fields), self._statsf istats(self, start=0, end=-1, fields=None):
          '''Perform a multivariate statistic calculation of this
  :class:`ColumnTS` from *start* to *end*.
  
  :param start: Optional index (rank) where to start the analysis.
  :param end: Optional index (rank) where to end the analysis.
  :param fields: Optional subset of :meth:`fields` to perform analysis on.
      If not provided all fields are included in the analysis.
  '''
          backend = self.read_backend
          return backend.execute(
              backend.structure(self).istats(start, end, fields), self._stats)
docs: Perform a multivariate statistic calculation of this
  :class:`ColumnTS` from *start* to *end*.
  
  :param start: Optional index (rank) where to start the analysis.
  :param end: Optional index (rank) where to end the analysis.
  :param fields: Optional subset of :meth:`fields` to perform analysis on.
      If not provided all fields are included in the analysis.