Fix BadRequestError

✅ Solution

The "BadRequestError" in pydantic, especially with `model_validator` and `mode='wrap'`, often arises because the validator is receiving the raw input data (e.g., a dictionary) instead of the partially validated model instance when it expects the latter. To fix this, ensure your validator's first argument is correctly annotated with `cls` when used as a class method or with `self` when used as an instance method, and appropriately typed with `RootModel[YourModel]` or `YourModel` to signal what type the validator expects, which helps pydantic pass the validated model. Additionally, confirm that the `handler` function within the wrapped validator correctly handles and modifies (or returns) the partially validated model before returning it for final validation.