Raise statement normalization in Lib/.
diff --git a/Lib/rfc822.py b/Lib/rfc822.py
index c4b7d37..1ad2d01 100644
--- a/Lib/rfc822.py
+++ b/Lib/rfc822.py
@@ -112,7 +112,7 @@
     def rewindbody(self):
         """Rewind the file to the start of the body (if seekable)."""
         if not self.seekable:
-            raise IOError, "unseekable file"
+            raise IOError("unseekable file")
         self.fp.seek(self.startofbody)
 
     def readheaders(self):