Update app.py

app.py

@@ -99,7 +99,7 @@ class OpalAgent:
         self.simplify_tool = SimplifyAnswerTool(self.llm)
         
         self.agent = CodeAgent(
-            llm=self.llm,
+            model=self.llm,
             tools=self.tools + [self.simplify_tool],
             verbose=False,
         )