用Python检测零售扫描中的缺货

Question

我收到了商店扫描机的数据。多亏了这一点，我正试图检测出Python的缺货。你知道吗

这里有两种情况：一种是高销量产品，另一种是低销量产品。你知道吗

╔═════════╦════════════╦══════════╦════════╗
║ Product ║    Date    ║ Quantity ║ Status ║
╠═════════╬════════════╬══════════╬════════╣
║ A       ║ 01/01/2018 ║       57 ║ ok     ║
║ A       ║ 02/01/2018 ║       79 ║ ok     ║
║ A       ║ 03/01/2018 ║       95 ║ ok     ║
║ A       ║ 04/01/2018 ║       81 ║ ok     ║
║ A       ║ 05/01/2018 ║       10 ║ ok     ║
║ A       ║ 06/01/2018 ║        5 ║ ok     ║
║ A       ║ 07/01/2018 ║        0 ║ oos    ║
║ A       ║ 08/01/2018 ║        0 ║ oos    ║
║ A       ║ 09/01/2018 ║        0 ║ oos    ║
║ A       ║ 10/01/2018 ║        0 ║ oos    ║
║ A       ║ 11/01/2018 ║       84 ║ ok     ║
║ A       ║ 12/01/2018 ║       37 ║ ok     ║
║ A       ║ 13/01/2018 ║       45 ║ ok     ║
║ A       ║ 14/01/2018 ║       50 ║ ok     ║
╚═════════╩════════════╩══════════╩════════╝

以及

╔═════════╦════════════╦══════════╦════════╗
║ Product ║    Date    ║ Quantity ║ Status ║
╠═════════╬════════════╬══════════╬════════╣
║ B       ║ 01/01/2018 ║        1 ║ ok     ║
║ B       ║ 02/01/2018 ║        0 ║ ok     ║
║ B       ║ 03/01/2018 ║        1 ║ ok     ║
║ B       ║ 04/01/2018 ║        3 ║ ok     ║
║ B       ║ 05/01/2018 ║        0 ║ ok     ║
║ B       ║ 06/01/2018 ║        1 ║ ok     ║
║ B       ║ 07/01/2018 ║        0 ║ ok     ║
║ B       ║ 08/01/2018 ║        0 ║ oos    ║
║ B       ║ 09/01/2018 ║        0 ║ oos    ║
║ B       ║ 10/01/2018 ║        0 ║ oos    ║
║ B       ║ 11/01/2018 ║        1 ║ ok     ║
║ B       ║ 12/01/2018 ║        2 ║ ok     ║
║ B       ║ 13/01/2018 ║        0 ║ ok     ║
║ B       ║ 14/01/2018 ║        1 ║ ok     ║
╚═════════╩════════════╩══════════╩════════╝

状态显示应该检测到的缺货，并且有数百万条记录，我正在使用python来处理这些数据。你知道吗

有没有什么模块/库/方法可以用python来检测它，即使是低销量的产品（不是说0销售=缺货，只是有些产品不是每天都买的）