update answer format

app.py

@@ -8,23 +8,21 @@ from langchain_core.messages import HumanMessage
 
 import re
 
-import re
-
 def extract_answer(text: str) -> str:
     """
     Clean and extract the final answer from agent output.
-    - Removes 'FINAL ANSWER:' if present.
-    - Strips trailing punctuation and whitespace.
-    - Normalizes comma/semicolon-separated lists.
+    Removes prefixes like 'FINAL ANSWER:', trims punctuation,
+    and normalizes separators.
     """
-    # 提取 FINAL ANSWER 后的内容（如果存在）
-    match = re.search(r"final answer[:：]?\s*(.+)", text, re.IGNORECASE)
-    answer = match.group(1) if match else text
+    # 提取 final answer 后内容
+    match = re.search(r"(final\s*answer|answer\s*is)[:：]?\s*(.+)", text, re.IGNORECASE)
+    answer = match.group(2) if match else text
 
-    # 去除结尾句号和首尾空格
-    answer = answer.strip().rstrip('.').strip()
+    # 清理格式
+    answer = answer.strip().lstrip(":").strip()     # ✅ 去掉前导冒号和空格
+    answer = answer.rstrip('.').strip()
 
-    # 多项答案的格式标准化（如 a , b -> a,b）
+    # 多项格式化
     if ',' in answer:
         answer = ",".join(part.strip() for part in answer.split(','))
     if ';' in answer:
@@ -33,6 +31,7 @@ def extract_answer(text: str) -> str:
     return answer
 
 
+
 # --- Constants ---
 DEFAULT_API_URL = "https://agents-course-unit4-scoring.hf.space"