# HG changeset patch
# User Pulkit Goyal <7895pulkit@gmail.com>
# Date 1463443356 -19800
# Node ID bac14dbbbfab840cb683f842ba52d959f5585ff7
# Parent  ad1ce3c7af720c8034b84416a9951553af2fcfcb
py3: use setattr() to assign new class attribute

The old method produces error 'object does not supports item assignment'.
So setattr() is used to assign a new class attribute via __dict__ .

diff -r ad1ce3c7af72 -r bac14dbbbfab mercurial/mail.py
--- a/mercurial/mail.py	Wed May 11 14:18:52 2016 -0700
+++ b/mercurial/mail.py	Tue May 17 05:32:36 2016 +0530
@@ -41,7 +41,7 @@
     kw['continuation_ws'] = ' '
     _oldheaderinit(self, *args, **kw)
 
-email.Header.Header.__dict__['__init__'] = _unifiedheaderinit
+setattr(email.header.Header, '__init__', _unifiedheaderinit)
 
 class STARTTLS(smtplib.SMTP):
     '''Derived class to verify the peer certificate for STARTTLS.