[Python] Pydantic validations for extra fields that not defined in schema

I am using pydantic for schema validations and I would like to throw an error when any extra field that isn't defined is added to a schema.

from typing import Literal, Union

from pydantic import BaseModel, Field, ValidationError


class Cat(BaseModel):
pet_type: Literal['cat']
meows: int


class Dog(BaseModel):
pet_type: Literal['dog']
barks: float


class Lizard(BaseModel):
pet_type: Literal['reptile', 'lizard']
scales: bool


class Model(BaseModel):
pet: Union[Cat, Dog, Lizard] = Field(..., discriminator='pet_type')
n: int


print(Model(pet={'pet_type': 'dog', 'barks': 3.14, 'eats': 'biscuit'}, n=1))
""" try:
Model(pet={'pet_type': 'dog'}, n=1)
except ValidationError as e:
print(e) """



In the above code, I have added the eats field which is not defined. The pydantic validations are applied and the extra values that I defined are removed in response. I want to throw an error saying eats is not allowed for Dog or something like that. Is there any way to achieve that?

And is there any chance that we can provide the input directly instead of the pet object?
print(Model({'pet_type': 'dog', 'barks': 3.14, 'eats': 'biscuit', n=1})). I tried without descriminator but those specific validations are missing related to pet_type. Can someone guide me how to achieve either one of that?

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