Suppose I have a student model, and what I want is that: if the age < 6, make the school optional.

What can I do? thanks in advance!

from pydantic import BaseModel

class Student(BaseModel):
    name: str
    age: int
    school: str

student = Student(**{ "name": "Tom", "age": 10, "school": "Blabla"}) # validated
baby_student = Student(**{ "name": "Tom", "age": 5}) # expected to be validated

what I have tried:

from pydantic import BaseModel, root_validator

class Student(BaseModel):
    name: str
    age: int
    school: str
    
    @root_validator(pre=True)
    def ignore_school_if_baby(cls, values):
        age = values.get("age")
        if age < 6:
            # don't know how to do here
            values["school"] = None
        return values

baby_student = Student(**{ "name": "Tom", "age": 10})