diff --git a/book_maker/config.py b/book_maker/config.py
index 96c9d78..a186a4a 100644
--- a/book_maker/config.py
+++ b/book_maker/config.py
@@ -1,8 +1,8 @@
 config = {
     "translator": {
         "chatgptapi": {
-            "context_paragraph_limit" : 3,
-            "batch_context_update_interval" : 50,
+            "context_paragraph_limit": 3,
+            "batch_context_update_interval": 50,
         }
     },
-}
\ No newline at end of file
+}
diff --git a/book_maker/translator/chatgptapi_translator.py b/book_maker/translator/chatgptapi_translator.py
index 4034245..c97121d 100644
--- a/book_maker/translator/chatgptapi_translator.py
+++ b/book_maker/translator/chatgptapi_translator.py
@@ -12,6 +12,7 @@ from rich import print
 
 from .base_translator import Base
 from ..config import config
+
 CHATGPT_CONFIG = config["translator"]["chatgptapi"]
 
 PROMPT_ENV_MAP = {
@@ -42,6 +43,7 @@ GPT4oMINI_MODEL_LIST = [
     "gpt-4o-mini-2024-07-18",
 ]
 
+
 class ChatGPTAPI(Base):
     DEFAULT_PROMPT = "Please help me to translate,`{text}` to {language}, please return only translated content not include the origin text"
 
@@ -486,9 +488,9 @@ class ChatGPTAPI(Base):
     def create_batch_context_messages(self, index):
         messages = []
         if self.context_flag:
-            if index % CHATGPT_CONFIG["batch_context_update_interval"] == 0 or not hasattr(
-                self, "cached_context_messages"
-            ):
+            if index % CHATGPT_CONFIG[
+                "batch_context_update_interval"
+            ] == 0 or not hasattr(self, "cached_context_messages"):
                 context_messages = []
                 for i in range(index - 1, -1, -1):
                     item = self.batch_text_list[i]