将dataframe数据加载到impala表时出错

DB = conn.cursor()
for row in fourth_set:
    SQL = ('''Insert into Boots_retailer(sale_date, product, Assessment, weekno, store_Number, volume, turnover, turnover_missing, Inv_Cubic, XGB, KNN) 
    values(?,?,?,?,?,?,?,?,?,?,?)''' )

    Values = row['Sale_date'], row['product'], row['Assessment'], row['weekno'],row['store_number'],
    row['volume'],row['turnover'],row['turnover_missing'],row['Inv_Cubic'],row['XGB'],row['KNN']

    har =  DB.execute(SQL, Values)
    connection.commit()

错误在线 Values = row['Sale_date'], ... :

TypeError: string indices must be integers, not str