required和additionalProperties对于jsonschema模块Python不起作用

我有以下代码:

from jsonschema import validate
schema_data = {
    "type" : "object",
    "properties" : {
        "price" : {"type" : "number"},
        "name" : {"type" : "string"},
        "additional" : {"type" : "number"},
        },
    "required": ["price", "name", "additional"],
    "additionalProperties": False
}

json_data = {"name" : "Eggs", "price" : 34.99, "new": 90}

这应该给我一个错误 required additionalProperties 作为 additional json_data 和 new 中不存在 schema_data . .

我需要一些额外的安装吗?我有以下配置:

Python 2.7.12,
jsonschema==3.0.1
attrs==19.1.0
six==1.12.0
pyrsistent==0.14.11