Update simple_sentiment.py

simple_sentiment.py

@@ -71,7 +71,7 @@ class SimpleSentimentTool(Tool):
                     raise RuntimeError(f"Failed to load any sentiment model: {str(e)}")
         return self._classifiers[model_id]
     
-    def forward(self, text: str, model_key=None):
+    def forward(self, text: str, model_key="oliverguhr/german-sentiment-bert"):
         """Process input text and return sentiment predictions."""
         try:
             # Determine which model to use