Use dict.items to avoid unnecessary lookups. (#23415)

It's more efficient to iterate over key, value dict pairs instead of iterating over keys and performing value lookups on each iteration. It's also more idiomatic.

src/transformers/tools/agents.py

@@ -92,8 +92,7 @@ def _setup_default_tools():
     tools_module = main_module.tools
 
     remote_tools = get_remote_tools()
-    for task_name in TASK_MAPPING:
-        tool_class_name = TASK_MAPPING.get(task_name)
+    for task_name, tool_class_name in TASK_MAPPING.items():
         tool_class = getattr(tools_module, tool_class_name)
         description = tool_class.description
         HUGGINGFACE_DEFAULT_TOOLS[tool_class.name] = PreTool(task=task_name, description=description, repo_id=None)