diff --git a/ssod/models/soft_teacher.py b/ssod/models/soft_teacher.py
index 8fed150..1f53c25 100644
--- a/ssod/models/soft_teacher.py
+++ b/ssod/models/soft_teacher.py
@@ -164,7 +164,7 @@ def rpn_loss(
                 "rpn_proposal", self.student.test_cfg.rpn
             )
             proposal_list = self.student.rpn_head.get_bboxes(
-                *rpn_out, img_metas == img_metas, cfg=proposal_cfg
+                *rpn_out, img_metas=img_metas, cfg=proposal_cfg
             )
             log_image_with_boxes(
                 "rpn",