Update app.py

Update of search function so the tool uses __call__ method instead of search attribute, which causes error

app.py

@@ -21,7 +21,7 @@ def web_search(query: str, max_results: int = 3) -> str: #it's import to specify
         search_tool = DuckDuckGoSearchTool()
 
         # Perform the search
-        results = search_tool.search(query, max_results=max_results)
+        results = search_tool(query, max_results=max_results)
 
         # Format the results
         formatted_results = []