Sahi segmentation to coco format: are all polygons taken into account?

[ninafiona]

I have a question regarding the conversion from sahi boolean mask to coco segmentation.
In the function to_coco_segmentation (in sahi/utils/cv.py) polygons are found using opencv and then the first or second contour is selected. Why are not all found polygon contours taken into account?

polygons = cv2.findContours(mask, cv2.RETR_LIST, cv2.CHAIN_APPROX_SIMPLE, offset=(-1, -1))
polygons = polygons[0] if len(polygons) == 2 else polygons[1]

Link to line in code

[ninafiona]

It seems findContours returns contours, hierarchy so in that case the contours are selected and maybe in an older version if three values are returned the second one are the polygons.