def fetch(self, fetch_notes=None):
        """ update remote values (called automatically at __init__) """
        if fetch_notes is None:
            fetch_notes = self.fetch_notes
        values, notes_index = get_sheet_values(self.name, self.sheet_name,
                                               spreadsheet_service=self._spreadsheet_service,
                                               get_notes=fetch_notes)
        self.raw_values = values
        self.values = [list(r) for r in zip(*itertools.zip_longest(*self.raw_values, fillvalue=''))]
        self.byCol = byCol(self.values, to_index=self.index_columns)
        self.notes_index = notes_index
update remote values (called automatically at __init__)