modify code structure

Former-commit-id: 6369f9b1751e6f9bb709ba76a85f69cbe0823e5d

src/cli_demo.py

@@ -3,11 +3,10 @@
 # Usage: python cli_demo.py --model_name_or_path path_to_model --checkpoint_dir path_to_checkpoint
 
 from llmtuner import ChatModel
-from llmtuner.tuner import get_infer_args
 
 
 def main():
-    chat_model = ChatModel(*get_infer_args())
+    chat_model = ChatModel()
     history = []
     print("Welcome to the CLI application, use `clear` to remove the history, use `exit` to exit the application.")