def apply_transform_keypoint(
        self, input: Keypoints, params: Dict[str, Tensor], flags: Dict[str, Any], transform: Optional[Tensor] = None
    ) -> Keypoints:
        """Process keypoints corresponding to the inputs that are transformed."""
        if transform is None:
            if self.transform_matrix is None:
                raise RuntimeError("No valid transformation matrix found. Please either pass one or forward one first.")
            transform = self.transform_matrix
        input = self.apply_non_transform_keypoint(input, params, flags, transform)
        return input.transform_keypoints_(transform)
Process keypoints corresponding to the inputs that are transformed.
kornia/augmentation/_2d/geometric/base.py