diff --git a/seafile_mirror/_cachedb.py b/seafile_mirror/_cachedb.py
index 206d0d0..81fb595 100755
--- a/seafile_mirror/_cachedb.py
+++ b/seafile_mirror/_cachedb.py
@@ -43,9 +43,7 @@ def db_update(dbdict, libid, **kwargs):
     if libid not in dbdict:
         dbdict[libid] = {}
     for key, value in kwargs.items():
-        logging.debug(
-            "Updating '%s' of library '%s' in in-memory cache dictionary", key, libid
-        )
+        logging.debug("Updating '%s' of library '%s' in in-memory cache dictionary", key, libid)
         dbdict[libid][key] = value
 
     db_write(dbdict)
diff --git a/seafile_mirror/_helpers.py b/seafile_mirror/_helpers.py
index 7620d73..3ecbddc 100755
--- a/seafile_mirror/_helpers.py
+++ b/seafile_mirror/_helpers.py
@@ -45,7 +45,7 @@ def convert_bytes(size):
     """Convert bytes to KB, MB etc depending on size"""
     power = 1024
     level = 0
-    labels = {0 : 'B', 1: 'KB', 2: 'MB', 3: 'GB', 4: 'TB'}
+    labels = {0: "B", 1: "KB", 2: "MB", 3: "GB", 4: "TB"}
     while size > power:
         size /= power
         level += 1
diff --git a/seafile_mirror/seafile_mirror.py b/seafile_mirror/seafile_mirror.py
index f23e786..c4866ea 100755
--- a/seafile_mirror/seafile_mirror.py
+++ b/seafile_mirror/seafile_mirror.py
@@ -121,16 +121,12 @@ def main():
             libid = lib["id"]
             # Set resync interval if there is a lib-specific setting. Otherwise default
             libresyncinterval = (
-                lib["resync_interval_days"]
-                if "resync_interval_days" in lib
-                else resyncinterval
+                lib["resync_interval_days"] if "resync_interval_days" in lib else resyncinterval
             )
 
             # Check if last sync of library is older than resync_interval_days
             if sf_lastsync_old_enough(cache, libid, args.force, libresyncinterval):
-                logging.info(
-                    "Starting to re-sync library %s (%s) to %s", libname, libid, libdir
-                )
+                logging.info("Starting to re-sync library %s (%s) to %s", libname, libid, libdir)
             else:
                 logging.info(
                     "Local mirror of library %s (%s) at %s is still recent enough. Skipping it.",
@@ -193,9 +189,7 @@ def main():
             # Get size of directory (libdir) in bytes
             # Note: this is not fully equivalent with what `du` would show. It's
             # caused by the fact that `du` considers filesystem block sizes
-            libdirsize = sum(
-                f.stat().st_size for f in libdir.glob("**/*") if f.is_file()
-            )
+            libdirsize = sum(f.stat().st_size for f in libdir.glob("**/*") if f.is_file())
 
             # Update libsdone and cache
             libsdone["libs"].append(libname)