--- a/hgext/transplant.py	Mon Feb 13 20:06:38 2017 +0530
+++ b/hgext/transplant.py	Mon Feb 13 22:15:28 2017 +0530
@@ -28,6 +28,7 @@
     merge,
     node as nodemod,
     patch,
+    pycompat,
     registrar,
     revlog,
     revset,
@@ -197,7 +198,7 @@
                     patchfile = None
                 else:
                     fd, patchfile = tempfile.mkstemp(prefix='hg-transplant-')
-                    fp = os.fdopen(fd, 'w')
+                    fp = os.fdopen(fd, pycompat.sysstr('w'))
                     gen = patch.diff(source, parent, node, opts=diffopts)
                     for chunk in gen:
                         fp.write(chunk)
@@ -245,7 +246,7 @@
         self.ui.status(_('filtering %s\n') % patchfile)
         user, date, msg = (changelog[1], changelog[2], changelog[4])
         fd, headerfile = tempfile.mkstemp(prefix='hg-transplant-')
-        fp = os.fdopen(fd, 'w')
+        fp = os.fdopen(fd, pycompat.sysstr('w'))
         fp.write("# HG changeset patch\n")
         fp.write("# User %s\n" % user)
         fp.write("# Date %d %d\n" % date)