Fix imagenet when importing a dataset with non-directory files (openv…

…inotoolkit#1179)

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src/datumaro/plugins/data_formats/imagenet.py

@@ -6,6 +6,7 @@
 import logging as log
 import os
 import os.path as osp
+import warnings
 from typing import Optional
 
 from datumaro.components.annotation import AnnotationType, Label, LabelCategories
@@ -44,7 +45,11 @@ def _load_categories(self, path):
         label_cat = LabelCategories()
         for dirname in sorted(os.listdir(path)):
             if not os.path.isdir(os.path.join(path, dirname)):
-                raise NotADirectoryError(errno.ENOTDIR, os.strerror(errno.ENOTDIR), path)
+                warnings.warn(
+                    f"{dirname} is not a directory in the folder {path}, so this will"
+                    "be skipped when declaring the cateogries of `imagenet` dataset."
+                )
+                continue
             if dirname != ImagenetPath.IMAGE_DIR_NO_LABEL:
                 label_cat.add(dirname)
         return {AnnotationType.label: label_cat}