diff --git a/src/calibre/gui2/tweak_book/check.py b/src/calibre/gui2/tweak_book/check.py
index 2813731a57..6e87c2eaf7 100644
--- a/src/calibre/gui2/tweak_book/check.py
+++ b/src/calibre/gui2/tweak_book/check.py
@@ -260,5 +260,6 @@ def main():
     d.show()
     app.exec_()
 
+
 if __name__ == '__main__':
     main()