fix import COCO_CATEGORIES in prepare_panoptic_fpn.py
Summary:
Simple fix, should be trivial to check.
Pull Request resolved:
@@ -9,7 +9,7 @@ import numpy as np
import os
from PIL import Image
-from detectron2.data.datasets.builtin import COCO_CATEGORIES
+from detectron2.data.datasets.builtin_meta import COCO_CATEGORIES
from fvcore.common.download import download
from panopticapi.utils import rgb2id
