from sqlalchemy import create_engine
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy.orm import sessionmaker, Column, Integer

engine = create_engine('sqlite:///:memory:')
Session = sessionmaker(bind=engine)
session =
Model = declarative_base()

class ToDo(Model):
    id = Column(Integer, primary_key=True)
    ...

Model.metadata.create_all(engine)
session = Session()
todos = session.query(ToDo).all()

from sqla_wrapper import SQLAlchemy

db = SQLAlchemy('sqlite:///:memory:')

class ToDo(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    ...

db.create_all()
todos = db.query(ToDo).all()