diff --git a/offlineimap/folder/Base.py b/offlineimap/folder/Base.py
index 3a04ef6..bdae5c3 100644
--- a/offlineimap/folder/Base.py
+++ b/offlineimap/folder/Base.py
@@ -197,7 +197,7 @@ class BaseFolder(object):
             return True
 
     def _getuidfilename(self):
-        """provides UIDVALIDITY cache filename for class internal purposes.
+        """provides UIDVALIDITY cache filename for class internal purposes."""
 
         return os.path.join(self.repository.getuiddir(),
                             self.getfolderbasename())