Update app.py

app.py

@@ -83,7 +83,7 @@ final_answer = FinalAnswerTool()
 
 model = LiteLLMModel(
         model_id="ollama_chat/qwen2:7b",  # Or try other Ollama-supported models
-        api_base=str(os.getenv(key=ollama_server_ip)),  # Default Ollama local server
+        api_base=os.getenv(key='ollama_server_ip'),  # Default Ollama local server
         num_ctx=8192,
     )