Update app.py

Fixed None runtime error pm get_web_search_results

app.py

@@ -27,7 +27,7 @@ def get_web_search_results(query: str)-> str: #it's import to specify the return
     """
     try:
         results = DuckDuckGoSearchTool.forward(query)
-        if results not None:
+        if results:
             return results
         else:
             return "Your query may be incorrectly formatted. Ensure it is of type str e.g. 'bananas'"