diff --git a/runtime/Python2/src/antlr4/atn/PredictionMode.py b/runtime/Python2/src/antlr4/atn/PredictionMode.py
index 0980ba773..8e6f5cdce 100644
--- a/runtime/Python2/src/antlr4/atn/PredictionMode.py
+++ b/runtime/Python2/src/antlr4/atn/PredictionMode.py
@@ -213,7 +213,7 @@ class PredictionMode(object):
                 # dup configs, tossing out semantic predicates
                 dup = ATNConfigSet()
                 for c in configs:
-                    c = ATNConfig(c,SemanticContext.NONE)
+                    c = ATNConfig(config=c, semantic=SemanticContext.NONE)
                     dup.add(c)
                 configs = dup
             # now we have combined contexts for configs with dissimilar preds
diff --git a/runtime/Python3/src/antlr4/atn/PredictionMode.py b/runtime/Python3/src/antlr4/atn/PredictionMode.py
index 67039c728..462fafc63 100644
--- a/runtime/Python3/src/antlr4/atn/PredictionMode.py
+++ b/runtime/Python3/src/antlr4/atn/PredictionMode.py
@@ -216,7 +216,7 @@ class PredictionMode(Enum):
                 # dup configs, tossing out semantic predicates
                 dup = ATNConfigSet()
                 for c in configs:
-                    c = ATNConfig(c,SemanticContext.NONE)
+                    c = ATNConfig(config=c, semantic=SemanticContext.NONE)
                     dup.add(c)
                 configs = dup
             # now we have combined contexts for configs with dissimilar preds