diff --git a/src/calibre/customize/builtins.py b/src/calibre/customize/builtins.py
index 53ddfeb059..2b27dcb008 100644
--- a/src/calibre/customize/builtins.py
+++ b/src/calibre/customize/builtins.py
@@ -578,6 +578,7 @@ class TXTZMetadataWriter(MetadataWriterPlugin):
         from calibre.ebooks.metadata.extz import set_metadata
         set_metadata(stream, mi)
 
+
 class ODTMetadataWriter(MetadataWriterPlugin):
 
     name        = 'Set ODT metadata'
@@ -588,6 +589,7 @@ class ODTMetadataWriter(MetadataWriterPlugin):
         from calibre.ebooks.metadata.odt import set_metadata
         return set_metadata(stream, mi)
 
+
 class DocXMetadataWriter(MetadataWriterPlugin):
 
     name        = 'Set DOCX metadata'