DeAdmin | 一个用VueJSAdminLTE实现的后台管理系统

In my Django model, I defined a @property which worked nicely and the property can be shown in the admin list_display without any problems.

I need this property not only in admin but in my code logic in other places as well, so it makes sense to have it as property for my model.

Now I wanted to make the column of this property sortable, and with help of the Django documentation of the When object, this StackOverflow question for the F()-calculation and this link for the sorting I managed to build the working solution shown below.

The reason for posing a question here is: In fact, I implemented my logic twice, once in python and once in form of an expression, which is against the design rule of implementing the same logic only once. So I wanted to ask whether I missed a better solution to my problem. Any ideas are appreciated.

This is the model (identifyers modified):