diff --git a/Integrations/src/main/java/io/deephaven/integrations/python/PythonMergedListenerAdapter.java b/Integrations/src/main/java/io/deephaven/integrations/python/PythonMergedListenerAdapter.java
index 2eea2a9c601..e498b60cf70 100644
--- a/Integrations/src/main/java/io/deephaven/integrations/python/PythonMergedListenerAdapter.java
+++ b/Integrations/src/main/java/io/deephaven/integrations/python/PythonMergedListenerAdapter.java
@@ -59,7 +59,7 @@ private PythonMergedListenerAdapter(
             @NotNull PyObject pyOnFailureCallback) {
         super(Arrays.asList(recorders), Arrays.asList(dependencies), listenerDescription, null);
         Arrays.stream(recorders).forEach(rec -> rec.setMergedListener(this));
-        this.pyListenerCallable = PythonUtils.pyMergeListenerFunc(pyListener);
+        this.pyListenerCallable = PythonUtils.pyMergeListenerFunc(Objects.requireNonNull(pyListener));
         this.pyOnFailureCallback = Objects.requireNonNull(pyOnFailureCallback);
     }
 
diff --git a/Integrations/src/main/java/io/deephaven/integrations/python/PythonReplayListenerAdapter.java b/Integrations/src/main/java/io/deephaven/integrations/python/PythonReplayListenerAdapter.java
index 2a3eedd6cd8..9cbfed65ec5 100644
--- a/Integrations/src/main/java/io/deephaven/integrations/python/PythonReplayListenerAdapter.java
+++ b/Integrations/src/main/java/io/deephaven/integrations/python/PythonReplayListenerAdapter.java
@@ -77,7 +77,7 @@ private PythonReplayListenerAdapter(
             @Nullable NotificationQueue.Dependency... dependencies) {
         super(description, source, retain);
         this.dependencies = dependencies;
-        this.pyListenerCallable = PythonUtils.pyListenerFunc(pyListener);
+        this.pyListenerCallable = Objects.requireNonNull(PythonUtils.pyListenerFunc(pyListener));
         this.pyOnFailureCallback = Objects.requireNonNull(pyOnFailureCallback);
     }