为什么在尝试使用pydantic验证JSON数据时,我会得到“使用不正确字段定义的验证器”?

没有包含的模型 grade 和 subject 领域。

from pydantic import BaseModel, validator
from typing import List, Optional
from datetime import date, time


class ClassTime(BaseModel):
    date: Optional[date]
    time: Optional[time]


class Subject(BaseModel):
    physics: str
    chemistry: str
    classTime: Optional[ClassTime]
    labTime: Optional[str]


class Student(BaseModel):
    grade: str
    subject: List[Subject]

    @validator("grade")
    def validate_grade(cls, val):
        if val is None:
            raise ValueError("grade is null")
        return val

    @validator("subject", each_item=True)
    def validate_subject(cls, val):
        if val.classTime:
            if not val.classTime.date:
                raise ValueError("classTime.date is null")
        return val


json_data = {
    "grade": "A",
    "subject": [
        {
            "physics": "PHY",
            "chemistry": "CHE",
            "classTime": {
                "date": "2024-03-25",
                "time": None
            },
            "labTime": None
        }
    ]
}

student = Student(**json_data)
print(student)

输出

grade='A' subject=[Subject(physics='PHY', chemistry='CHE', classTime=ClassTime(date=datetime.date(2024, 3, 25), time=None), labTime=None)]