sqlalchemy.orm.exc.UnmappedInstanceError: Class 'builtins.list' is not mapped

修改前

@app.route('/add_course')
def add_course():
    course1 = Course('python基础')
    course2 = Course('Python高级')
    course3 = Course('Python web基础')
    course4 = Course('Python web 开发')

    db.session.add([course1, course2, course3, course4])
    return 'Add course OK'

修改后

@app.route('/add_course')
def add_course():
    course1 = Course('python基础')
    course2 = Course('Python高级')
    course3 = Course('Python web基础')
    course4 = Course('Python web 开发')

    # 下面的add改成add_all就好了
    db.session.add_all([course1, course2, course3, course4])
    return 'Add course OK'

错误原因：
一次添加多条不是add而是add_all