refactor: convert final_answer function to FinalAnswerTool class for improved structure and extensibility

src/final_answer_tool.py

@@ -1,11 +1,14 @@
 from typing import Any, Optional
-from smolagents import tool
+from smolagents.tools import Tool
 
-@tool(
-    name="final_answer",
-    description="Provides a final answer to the given problem.",
-    inputs={'answer': {'type': 'any', 'description': 'The final answer to the problem'}},
-    output_type="any"
-)
-def final_answer(answer: Any) -> Any:
-    return answer
+class FinalAnswerTool(Tool):
+    name = "final_answer"
+    description = "Provides a final answer to the given problem."
+    inputs = {'answer': {'type': 'any', 'description': 'The final answer to the problem'}}
+    output_type = "any"
+
+    def forward(self, answer: Any) -> Any:
+        return answer
+
+    def __init__(self, *args, **kwargs):
+        self.is_initialized = False