modify some style

src/llmtuner/data/preprocess.py

@@ -6,6 +6,7 @@ from ..extras.constants import IGNORE_INDEX
 from ..extras.logging import get_logger
 from .utils import Role
 
+
 if TYPE_CHECKING:
     from transformers import Seq2SeqTrainingArguments
     from transformers.tokenization_utils import AutoProcessor, PreTrainedTokenizer