TypeError: unsupported operand type(s) for +: 'Tensor' and 'tuple'

[qianqianderizi]

When I run "python tools/train.py configs/scene_graph/VG_SgDet_heth_area_mask_X_rcnn_x101_64x4d_fpn_1x.py",

There was an error:
File "/home/XXX/MMSceneGraph/mmdet/models/relation_heads/het_head.py", line 117, in forward
roi_feats, union_feats, det_result = self.frontend_features(img, img_meta, det_result, gt_result)
File "/home/XXX/MMSceneGraph/mmdet/models/relation_heads/relation_head.py", line 229, in frontend_features
return roi_feats + union_feats + (det_result,)
TypeError: unsupported operand type(s) for +: 'Tensor' and 'tuple'

but run "python tools/train.py configs/scene_graph/VG_SgCls_heth_area_mask_X_rcnn_x101_64x4d_fpn_1x.py" is no problem.
How can I solve the problem? thx.