Fix duplicated label import for Kaggle importer (#1244)

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Resolves #111 and #222.
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CHANGELOG.md

@@ -49,6 +49,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
   (<https://github.com/openvinotoolkit/datumaro/pull/1237>)
 - Fix a bug in the previous behavior when importing nested datasets in the project
   (<https://github.com/openvinotoolkit/datumaro/pull/1243>)
+- Fix Kaggle importer when adding duplicated labels
+  (<https://github.com/openvinotoolkit/datumaro/pull/1244>)
 
 ## 16/11/2023 - Release 1.5.1
 ### Enhancements

src/datumaro/plugins/data_formats/kaggle/base.py

@@ -307,13 +307,13 @@ def __init__(
         for img_filename in os.listdir(path):
             if not img_filename.lower().endswith(tuple(IMAGE_EXTENSIONS)):
                 continue
-            item_id = os.path.splitext(img_filename)[0]
+            item_id = osp.splitext(img_filename)[0]
 
-            img_file = os.path.join(path, img_filename)
-            ann_file = os.path.join(ann_path, item_id + self.ann_extensions)
+            img_file = osp.join(path, img_filename)
+            ann_file = osp.join(ann_path, item_id + self.ann_extensions)
 
             annotations = (
-                self._parse_annotations(img_file, ann_file) if os.path.isfile(ann_file) else []
+                self._parse_annotations(img_file, ann_file) if osp.isfile(ann_file) else []
             )
 
             media = Image.from_file(path=img_file, size=self._size)
@@ -351,8 +351,11 @@ def _parse_annotations(self, img_file: str, ann_file: str):
             ymin = self._parse_field(bbox_elem, "ymin", float)
             ymax = self._parse_field(bbox_elem, "ymax", float)
 
-            self._label_cat.add(label_name)
-            label_id, _ = self._label_cat.find(label_name)
+            label_id, cat = self._label_cat.find(label_name)
+            if not cat:
+                self._label_cat.add(label_name)
+                label_id, _ = self._label_cat.find(label_name)
+
             annotations.append(
                 Bbox(id=obj_id, label=label_id, x=xmin, y=ymin, w=xmax - xmin, h=ymax - ymin)
             )
@@ -419,7 +422,10 @@ def _parse_annotations(self, img_file: str, ann_file: str):
             w *= image_width
             h *= image_height
 
-            self._label_cat.add(label_name)
+            label_id, cat = self._label_cat.find(label_name)
+            if not cat:
+                self._label_cat.add(label_name)
+                label_id, _ = self._label_cat.find(label_name)
             label_id, _ = self._label_cat.find(label_name)
 
             annotations.append(Bbox(id=obj_id, label=label_id, x=x, y=y, w=w, h=h))