docs: def init_db_conn(connection_name, connection_string, scopefunc=None):
      """
      Initialize a postgresql connection by each connection string
      defined in the configuration file
      """
      engine = create_engine(connection_string)
      session = scoped_session(sessionmaker(), scopefunc=scopefunc)
      session.configure(bind=engine)
      pool.connections[connection_name] = Connection(engine, session)