diff --git a/bin/fpfs_process_descsim.py b/bin/fpfs_process_descsim.py
index f216bd4..9f753cc 100755
--- a/bin/fpfs_process_descsim.py
+++ b/bin/fpfs_process_descsim.py
@@ -13,6 +13,7 @@
 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 # GNU General Public License for more details.
 #
+
 import os
 import time
 import fpfs
diff --git a/fpfs/io.py b/fpfs/io.py
index 5abf7f3..d3e1656 100644
--- a/fpfs/io.py
+++ b/fpfs/io.py
@@ -9,10 +9,10 @@ def save_catalog(filename, arr, **kwargs):
     Save a numpy.ndarray to a fits file.
 
     Parameters:
-        arr (numpy.ndarray):
-            Numpy array to save.
         filename (str):
             Path of the output fits file.
+        arr (numpy.ndarray):
+            Numpy array to save.
     """
     for key, value in kwargs.items():
         if not isinstance(value, str):