Fix SQLAlchemy-related type errors

portal/__init__.py

@@ -9,7 +9,7 @@ from flask_sqlalchemy import SQLAlchemy
 
 from .db_config import get_database_uri, get_uri_for_sqlite
 
-db = SQLAlchemy()
+db: SQLAlchemy = SQLAlchemy()
 
 from .model import *
 

portal/model/FlaskConfigEntry.py

 from flask import Flask
+from flask_sqlalchemy import DefaultMeta
 
 from portal import db
 
+BaseModel: DefaultMeta = db.Model
 
-class FlaskConfigEntry(db.Model):
+
+class FlaskConfigEntry(BaseModel):
     """
     A configuration entry for Flask (a key-value pair) as persisted in a database
     """

portal/model/Retrievable.py

 from abc import abstractmethod
 from typing import Any, List, Optional, Self
+from flask_sqlalchemy import DefaultMeta
+from sqlalchemy import Column
 
 from flask import g
 
 from portal import db
 
+BaseModel: DefaultMeta = db.Model
 
-class Retrievable(db.Model):
+
+class Retrievable(BaseModel):
     """
     A type whose instances can be retrieved from the database.
 
@@ -17,7 +21,7 @@ class Retrievable(db.Model):
     __abstract__ = True
 
     @classmethod
-    def get_canonical_order_column(cls) -> Optional[db.Column]:
+    def get_canonical_order_column(cls) -> Optional[Column]:
         """
         Return the colum by which instances of this type should be canonically ordered
         when retrieving them all from the database.