diff --git a/mercurial/archival.py b/mercurial/archival.py
--- a/mercurial/archival.py
+++ b/mercurial/archival.py
@@ -146,7 +146,7 @@
                 self.timestamp = timestamp
             gzip.GzipFile.__init__(self, *args, **kw)
 
-        def _write_gzip_header(self):
+        def _write_gzip_header(self, *args, **kwargs):
             self.fileobj.write(b'\037\213')  # magic header
             self.fileobj.write(b'\010')  # compression method
             fname = self.name