def get_next_id(self):
        try:
            query = {'_id': 'last_id'}
            update = {'$inc': {'id': 1}}
            fn = self.db.internal.find_and_modify
            row = fn(query, update, upsert=True, new=True)
        except Exception as e:
            raise DatabaseException(e)
        return row['id']
def testName(self):
        plotter = VoltageProfilePlotter(xaxis="frac_x")
        plotter.add_electrode(self.ie_LTO, "LTO insertion")
        plotter.add_electrode(self.ce_FF, "FeF3 conversion")
        self.assertIsNotNone(plotter.get_plot_data(self.ie_LTO))
        self.assertIsNotNone(plotter.get_plot_data(self.ce_FF))