Fix error with DuckDuckGoSearchTool

DuckDuckGoSearchTool is not of type Tool and thus causes an error.

Pass an instantiation of DuckDuckGoSearchTool to CodeAgent.

app.py

@@ -46,13 +46,14 @@ custom_role_conversions=None,
 
 # Import tool from Hub
 image_generation_tool = load_tool("agents-course/text-to-image", trust_remote_code=True)
+search_tool = DuckDuckGoSearchTool()
 
 with open("prompts.yaml", 'r') as stream:
     prompt_templates = yaml.safe_load(stream)
     
 agent = CodeAgent(
     model=model,
-    tools=[final_answer, DuckDuckGoSearchTool, get_papers_url_for_date, get_current_time_in_timezone],
+    tools=[final_answer, search_tool, get_papers_url_for_date, get_current_time_in_timezone],
     max_steps=6,
     verbosity_level=1,
     grammar=None,