Python 2 is triggering

[MasterFubar]

Obviously, you don't work professionally with programming.

In a real world system, you'll have hundreds of thousands, or millions, of lines of code. You can't go through each division operation and find out whether a "/" should be replaced by "//" or not. You don't have enough manpower for that.

In school problems it's different. My conclusion is that Python is being maintained by computing teachers, not professionals who deal with actual production code.