diff --git a/apps/wpm/models.py b/apps/wpm/models.py
index ee86b37a..843dfad9 100644
--- a/apps/wpm/models.py
+++ b/apps/wpm/models.py
@@ -383,7 +383,7 @@ class Mlogbw(BaseModel):
     note = models.TextField('备注', null=True, blank=True)
 
     @classmethod
-    def cal_count_notok(mlogb: Mlog):
+    def cal_count_notok(cls, mlogb: Mlog):
         count = Mlogbw.objects.filter(mlogb=mlogb).count()
         if mlogb.material_in:
             mlogb.count_use = count