22.3.2: Possible wrong base class for ModelManager

[mschoettle]

Location within the Book

• Chapter or Appendix: 22
• Section: 3
• Subsection: 2
• Example: 22.9

Description

This is a follow-up to #136. I am in the process of implementing this and I use mypy for type checking.

Defining the manager using the base class BaseUserManager resolves in the following error for the following line:

objects = InventorManager()

Incompatible types in assignment (expression has type "InventorManager[Inventor]", base class "User" defined the type as "UserManager[User]") [assignment]mypy(error)

Possible Solutions

AbstractUser actually uses UserManager so I wonder if inheriting from UserManager would not be better. At the same time, it also resolves the mypy error.

Your full name so we can provide accurate credit within the book

Matthias Schoettle