example.py

from typing import Optional

import graphene
from graphene import Mutation, ObjectType, Field
from graphene_pydantic import PydanticInputObjectType, PydanticObjectType
from graphql import GraphQLResolveInfo
from pydantic import BaseModel


class UserUpdate(BaseModel):
    name: Optional[str]
    age: Optional[int]

      
class User(UserUpdate):
    pass


class UserUpdateInput(PydanticInputObjectType):
    class Meta:
        model = UserUpdate


class UserOutput(PydanticObjectType):
    class Meta:
        model = User


class UserUpdateSchema(Mutation):
    class Arguments:
        user = UserUpdateInput()

    Output = UserOutput

    @staticmethod
    def mutate(parent, info: GraphQLResolveInfo, user: dict) -> User:
        print(f"{user=}")  # {'name': None, 'age': 17}
        user_update_candidate = UserUpdate(**user)
        print(f"{user_update_candidate.dict(exclude_unset=True)=}")  # {'name': None, 'age': 17}
        ...
        return UserOutput(age=1, name="mark")


class Query(ObjectType):
    get_user = Field(UserOutput)


class UserMutation(ObjectType):
    user_update = UserUpdateSchema.Field()


schema = graphene.Schema(query=Query, mutation=UserMutation)


def handler():
    mutation = """
    mutation {
        userUpdate(user: {
            age: 17
        }) {
            age
            name
        }
    }
    """
    schema.execute(mutation)


if __name__ == '__main__':
    handler()