Comment by FreakLegion

The Annotated type is worth mentioning as well. Today in something like SQLModel you do (from the readme):

    class Hero(SQLModel, table=True):
        id: Optional[int] = Field(default=None, primary_key=True)

And that's fine. I wouldn't necessarily change anything here. Annotated gives you the option of approaching things in a different way, though.

    class Hero(SQLModel, table=True):
        id: PrimaryKey[Optional[int]] = None

I have some use cases where the alternative approach is useful, like quantification of class fields or function arguments.