fix lm-eval task

lm-eval-task/utils.py

@@ -49,12 +49,13 @@ def extract_longest_def_solve_code_block(text: str) -> dict | None:
     # Matches ```language followed by content until ```
     pattern = r'```([a-zA-Z0-9]+)\s*(.*?)\s*```'
     matches = re.findall(pattern, text, re.DOTALL)
-    
     if not matches:
         return None
     
     # Filter only those including the solve definition
     matches = [(lang, content) for lang, content in matches if 'def solve' in content]
+    if len(matches) == 0:
+        return None
           
     # Select longest by content length
     longest = max(matches, key=lambda x: len(x[1].strip()))