def add_items(self, items_list, incl_pmag=True, incl_parents=True):
        """
        Add items and/or update existing items in grid
        """
        num_rows = self.GetNumberRows()
        current_grid_rows = [self.GetCellValue(num, 0) for num in range(num_rows)]
        er_data = {item.name: item.er_data for item in items_list}
        pmag_data = {item.name: item.pmag_data for item in items_list}
        items_list = sorted(items_list, key=lambda item: item.name)
        for item in items_list[:]:
            if item.name in current_grid_rows:
                pass
            else:
                self.add_row(item.name, item)
        self.add_data(er_data)#, pmag=False)
        if incl_pmag:
            self.add_data(pmag_data, pmag=True)
        if incl_parents:
            self.add_parents()