diff --git a/.gitignore b/.gitignore
index f26b8e6..e2f2aaa 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,2 +1,3 @@
 .idea/
+__pycache__/
 test/
diff --git a/simple_backup/simple_backup.py b/simple_backup/simple_backup.py
index b349f19..efcc66c 100755
--- a/simple_backup/simple_backup.py
+++ b/simple_backup/simple_backup.py
@@ -185,9 +185,10 @@ class Backup:
                     fp.write('\n')
 
         with open(self._exclude_path, 'w') as fp:
-            for e in self.exclude:
-                fp.write(e)
-                fp.write('\n')
+            if self.exclude is not None:
+                for e in self.exclude:
+                    fp.write(e)
+                    fp.write('\n')
 
         if self.keep != -1 and self.remove_before:
             self.remove_old_backups()