Issue #4537: webbrowser.UnixBrowser failed because this module defines an open()
function which shadows the builtin.

Will backport to 3.0
diff --git a/Lib/webbrowser.py b/Lib/webbrowser.py
index 4772adc..18dc11b 100644
--- a/Lib/webbrowser.py
+++ b/Lib/webbrowser.py
@@ -223,7 +223,7 @@
         cmdline = [self.name] + raise_opt + args
 
         if remote or self.background:
-            inout = open(os.devnull, "r+")
+            inout = io.open(os.devnull, "r+")
         else:
             # for TTY browsers, we need stdin/out
             inout = None