refine templates of graph (#1368)

### What problem does this PR solve?

#918 
### Type of change

- [x] New Feature (non-breaking change which adds functionality)

rag/llm/cv_model.py

@@ -108,6 +108,7 @@ class AzureGptV4(Base):
         )
         return res.choices[0].message.content.strip(), res.usage.total_tokens
 
+
 class QWenCV(Base):
     def __init__(self, key, model_name="qwen-vl-chat-v1", lang="Chinese", **kwargs):
         import dashscope