sa_init.py

from sqlalchemy import create_engine
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy.orm import sessionmaker
from sqlalchemy import Table, Column, Integer, ForeignKey
from sqlalchemy.orm import relationship, backref


engine = create_engine('sqlite:///:memory:', echo=True)
Base = declarative_base()
Base.metadata.bind = engine
Session = sessionmaker(bind=engine)
session = Session()

# Define models here



Base.metadata.create_all()