diff --git a/Lib/mailbox.py b/Lib/mailbox.py
index 3866953..b1e5faa 100644
--- a/Lib/mailbox.py
+++ b/Lib/mailbox.py
@@ -1774,7 +1774,7 @@
     """Message with Babyl-specific properties."""
 
     def __init__(self, message=None):
-        """Initialize an BabylMessage instance."""
+        """Initialize a BabylMessage instance."""
         self._labels = []
         self._visible = Message()
         Message.__init__(self, message)