diff --git a/examples/dataset_pfs_workflow/pfs/pfs_cross_transfer.py b/examples/dataset_pfs_workflow/pfs/pfs_cross_transfer.py
index 93a3fa3..5f69127 100644
--- a/examples/dataset_pfs_workflow/pfs/pfs_cross_transfer.py
+++ b/examples/dataset_pfs_workflow/pfs/pfs_cross_transfer.py
@@ -85,7 +85,9 @@ def get_split_errs(algo):
                 split = train_xs.shape[0] - proportion_list[tmp]
 
                 model.fit(
-                    train_xs[split:,],
+                    train_xs[
+                        split:,
+                    ],
                     train_ys[split:],
                     eval_set=[(val_xs, val_ys)],
                     early_stopping_rounds=50,
diff --git a/learnware/client/utils.py b/learnware/client/utils.py
index 1aa6651..09e5142 100644
--- a/learnware/client/utils.py
+++ b/learnware/client/utils.py
@@ -13,15 +13,14 @@ def system_execute(args, timeout=None, env=None, stdout=subprocess.DEVNULL, stde
     if env is None:
         env = os.environ.copy()
         pass
-    
+
     if isinstance(args, str):
         pass
     else:
-        args = ' '.join(args)
+        args = " ".join(args)
         pass
-        
-    com_process = subprocess.run(
-        args, stdout=stdout, stderr=stderr, timeout=timeout, env=env, shell=True)
+
+    com_process = subprocess.run(args, stdout=stdout, stderr=stderr, timeout=timeout, env=env, shell=True)
 
     try:
         com_process.check_returncode()