diff --git a/Lib/compiler/pyassem.py b/Lib/compiler/pyassem.py
index 5932ffe..b59661f 100644
--- a/Lib/compiler/pyassem.py
+++ b/Lib/compiler/pyassem.py
@@ -744,6 +744,7 @@
     effect = {
         'POP_TOP': -1,
         'DUP_TOP': 1,
+        'LIST_APPEND': -2,
         'SLICE+1': -1,
         'SLICE+2': -1,
         'SLICE+3': -2,