Transpose bounding box (flip or rotate in 90 degree steps)
        :param method: One of :py:attr:`PIL.Image.FLIP_LEFT_RIGHT`,
          :py:attr:`PIL.Image.FLIP_TOP_BOTTOM`, :py:attr:`PIL.Image.ROTATE_90`,
          :py:attr:`PIL.Image.ROTATE_180`, :py:attr:`PIL.Image.ROTATE_270`,
          :py:attr:`PIL.Image.TRANSPOSE` or :py:attr:`PIL.Image.TRANSVERSE`.

def transpose(self, method):
        """
        Transpose bounding box (flip or rotate in 90 degree steps)
        :param method: One of :py:attr:`PIL.Image.FLIP_LEFT_RIGHT`,
          :py:attr:`PIL.Image.FLIP_TOP_BOTTOM`, :py:attr:`PIL.Image.ROTATE_90`,
          :py:attr:`PIL.Image.ROTATE_180`, :py:attr:`PIL.Image.ROTATE_270`,
          :py:attr:`PIL.Image.TRANSPOSE` or :py:attr:`PIL.Image.TRANSVERSE`.
        """
        if method not in (FLIP_LEFT_RIGHT, FLIP_TOP_BOTTOM):
            raise NotImplementedError(
                "Only FLIP_LEFT_RIGHT and FLIP_TOP_BOTTOM implemented"
            )

        image_width, image_height = self.size
        xmin, ymin, xmax, ymax = self._split_into_xyxy()
        if method == FLIP_LEFT_RIGHT:
            TO_REMOVE = 1
            transposed_xmin = image_width - xmax - TO_REMOVE
            transposed_xmax = image_width - xmin - TO_REMOVE
            transposed_ymin = ymin
            transposed_ymax = ymax
        elif method == FLIP_TOP_BOTTOM:
            transposed_xmin = xmin
            transposed_xmax = xmax
            transposed_ymin = image_height - ymax
            transposed_ymax = image_height - ymin

        transposed_boxes = torch.cat(
            (transposed_xmin, transposed_ymin, transposed_xmax, transposed_ymax), dim=-1
        )
        bbox = BoxList(transposed_boxes, self.size, mode="xyxy")
        # bbox._copy_extra_fields(self)
        for k, v in self.extra_fields.items():
            if not isinstance(v, torch.Tensor):
                v = v.transpose(method)
            bbox.add_field(k, v)
        return bbox.convert(self.mode)