refactor: import vllm when necessary

codecritic/data/cov.py

@@ -13,7 +13,6 @@ from codecritic.utils.data import (
     save_jsonl_dataset,
     SPLITTER,
 )
-from codecritic.utils.vllm import vllm_chatcomplete
 
 COV_PROMPT = "Please verify your code step by step using Markdown code blocks. After each step, explain whether it's correct or not, and if not, explain the issue."
 
@@ -84,6 +83,8 @@ def convert_cov_to_cov_dataset(item):
 
 
 if __name__ == "__main__":
+    from codecritic.utils.vllm import vllm_chatcomplete
+
     parser = argparse.ArgumentParser()
     parser.add_argument("--model", type=str)
     parser.add_argument("--preference_dataset", type=str)