fixed bug

yolov8.py

@@ -112,8 +112,9 @@ class YOLOv8Face:
         landmarks = landmarks[mask]
         
         indices = cv2.dnn.NMSBoxes(bboxes_wh.tolist(), confidences.tolist(), self.conf_threshold,
-                                   self.iou_threshold).flatten()
+                                   self.iou_threshold)
         if len(indices) > 0:
+            indices = indices.flatten()
             mlvl_bboxes = bboxes_wh[indices]
             confidences = confidences[indices]
             classIds = classIds[indices]