What is the correct way of using Flask-Sqlalchemy with multiprocessing?

from sqlalchemy import create_engine
from sqlalchemy.orm import sessionmaker

def worker(row_id):    
    db_url = os.environ['DATABASE_URL']
    db_engine = create_engine(db_url)
    Session = sessionmaker(bind=db_engine)
    db_session = Session()

    # Do stuff with db_session here

    db_session.close()