Issue #2333: Backport set and dict comprehensions syntax.
diff --git a/Lib/compiler/pyassem.py b/Lib/compiler/pyassem.py
index 88510de..286be0c 100644
--- a/Lib/compiler/pyassem.py
+++ b/Lib/compiler/pyassem.py
@@ -685,7 +685,9 @@
     effect = {
         'POP_TOP': -1,
         'DUP_TOP': 1,
-        'LIST_APPEND': -2,
+        'LIST_APPEND': -1,
+        'SET_ADD': -1,
+        'MAP_ADD': -2,
         'SLICE+1': -1,
         'SLICE+2': -1,
         'SLICE+3': -2,