--- lib/python3.4/gzip.py~	2013-09-09 22:21:08.203447446 -0400
+++ lib/python3.4/gzip.py	2013-10-09 20:58:24.383865730 -0400
@@ -201,7 +201,7 @@
             self.min_readsize = 100
             fileobj = _PaddedFile(fileobj)
 
-        elif mode.startswith(('w', 'a')):
+        elif mode.startswith(('w', 'a', 'x')):
             self.mode = WRITE
             self._init_write(filename)
             self.compress = zlib.compressobj(compresslevel,