diff --git a/modules/mol/alg/pymod/scoring.py b/modules/mol/alg/pymod/scoring.py
index e3fd114cec900ce8025bee6fd3932c2209f8a6ec..b4ce2f605e3bc7b3d40d4d6ec22c07862941c1db 100644
--- a/modules/mol/alg/pymod/scoring.py
+++ b/modules/mol/alg/pymod/scoring.py
@@ -1623,7 +1623,7 @@ class Scorer:
                 trg_ch2 = interface[1]
                 res = dockq.DockQ(self.target, self.target,
                                   trg_ch1, trg_ch2, trg_ch1, trg_ch2)
-                not_covered_counts.apend(res["nnat"])
+                not_covered_counts.append(res["nnat"])
   
         # there are 4 types of combined scores
         # - simple average