diff --git a/main_windows.py b/main_windows.py
index 3503163..ecd4b3a 100644
--- a/main_windows.py
+++ b/main_windows.py
@@ -58,7 +58,6 @@
 os.makedirs(DOWNLOAD_FOLDER, exist_ok=True)
 os.makedirs(CACHE_FOLDER, exist_ok=True)
 
-
 # --- --- --- Section Load Session --- --- --- #
 
 if args.session_cookie is not None:
@@ -69,6 +68,7 @@
     import websocket
     import qrcode
 
+
     def on_message(ws, message):
         global userinfo
         userinfo = json.loads(message)
@@ -106,7 +106,7 @@
 
     # Store session
     with open(f"{DOWNLOAD_FOLDER}/session.txt", "a", encoding='utf-8') as f:
-        f.write(rainclassroom_sess.cookies['sessionid']+ "\n")
+        f.write(rainclassroom_sess.cookies['sessionid'] + "\n")
 
 # --- --- --- Section Get Course List --- --- --- #
 
@@ -187,7 +187,6 @@
     lesson_video_data = rainclassroom_sess.get(
         f"https://{YKT_HOST}/api/v3/lesson-summary/replay?lesson_id={lesson['courseware_id']}").json()
 
-
     name_prefix += "-" + lesson['title'].rstrip()
     # Remove illegal characters for Windows filenames
     name_prefix = re.sub(r'[<>:"\\|?*\xa0]', '_', name_prefix)
@@ -232,7 +231,8 @@
             concatenate_segments(CACHE_FOLDER, DOWNLOAD_FOLDER, name_prefix, len(lesson_video_data['data']['live']))
         elif 'live_timeline' in lesson_video_data['data'] and len(lesson_video_data['data']['live_timeline']) > 0:
             print(f"Concatenating {name_prefix}")
-            concatenate_segments(CACHE_FOLDER, DOWNLOAD_FOLDER, name_prefix, len(lesson_video_data['data']['live_timeline']))
+            concatenate_segments(CACHE_FOLDER, DOWNLOAD_FOLDER, name_prefix,
+                                 len(lesson_video_data['data']['live_timeline']))
         else:
             print('concatenate cannot start due to previous failure')
     else:
@@ -281,7 +281,7 @@
             try:
                 ppt_raw_data = rainclassroom_sess.get(
                     f"https://{YKT_HOST}/api/v3/lesson-summary/student/presentation?presentation_id={ppt['id']}&lesson_id={lesson["courseware_id"]}").json()
-                download_ppt(3,args.ppt_problem_answer, args.ppt_to_pdf, CACHE_FOLDER, DOWNLOAD_FOLDER,
+                download_ppt(3, args.ppt_problem_answer, args.ppt_to_pdf, CACHE_FOLDER, DOWNLOAD_FOLDER,
                              ppt_raw_data, name_prefix + f"-{index}")
 
             except Exception as e:
diff --git a/video_processing.py b/video_processing.py
index 5d9f89c..9581519 100644
--- a/video_processing.py
+++ b/video_processing.py
@@ -1,9 +1,8 @@
 from concurrent.futures import ThreadPoolExecutor, as_completed
-import subprocess,sys
+import subprocess, sys
 
 
-def download_segment(CACHE_FOLDER, url: str, order: int, name_prefix: str = "" ):
-
+def download_segment(CACHE_FOLDER, url: str, order: int, name_prefix: str = ""):
     print(f"Downloading {name_prefix} - {order}")
 
     video_download_command = (f".\\aria2c -o '{CACHE_FOLDER}/{name_prefix}-{order}.mp4'"
@@ -12,8 +11,8 @@
 
     return result
 
-def download_segment_m3u8(CACHE_FOLDER, url: str, order: int, name_prefix: str = "" ):
 
+def download_segment_m3u8(CACHE_FOLDER, url: str, order: int, name_prefix: str = ""):
     print(f"Downloading {name_prefix} - {order}")
 
     # video_download_command = (f".\\ffmpeg -i '{url}' -c copy -n '{CACHE_FOLDER}/{name_prefix}-{order}.mp4'"
@@ -62,10 +61,11 @@
     if fallback_flag:
         # Create a ThreadPoolExecutor to manage parallel downloads
         with ThreadPoolExecutor(max_workers=6) as executor:
-             # Dictionary to hold future results
+            # Dictionary to hold future results
             if 'm3u8' in lesson_video_data['data']['live_timeline'][0]['replay_url']:
                 future_to_order = {
-                    executor.submit(download_segment_m3u8, CACHE_FOLDER, segment['replay_url'], order, name_prefix): order
+                    executor.submit(download_segment_m3u8, CACHE_FOLDER, segment['replay_url'], order,
+                                    name_prefix): order
                     for order, segment in enumerate(lesson_video_data['data']['live_timeline'])
                 }
             else:
@@ -115,7 +115,6 @@
 
 
 def concatenate_segments(CACHE_FOLDER, DOWNLOAD_FOLDER, name_prefix, num_segments):
-
     with open(f"{CACHE_FOLDER}/concat.txt", "w", encoding='utf-8') as f:
         f.write("\n".join(
             [f"file '../{CACHE_FOLDER}/{name_prefix}-{i}.mp4'" for i in range(num_segments)]
@@ -128,4 +127,4 @@
         f"-c:a aac -ac 1 -rematrix_maxval 1.0 -b:a 64k '{DOWNLOAD_FOLDER}/{name_prefix}.mp4' -n "
         f"-hide_banner -loglevel error -stats")
 
-    subprocess.run(['powershell', '-Command', video_concatenating_command], text=True)
\ No newline at end of file
+    subprocess.run(['powershell', '-Command', video_concatenating_command], text=True)