[Python] Простая отправка сообщения с не-аски символами

gistfile1.py

# coding: utf-8
import smtplib
from email.mime.text import MIMEText
from email.Header import Header
from email.Utils import formataddr

# settings
charset = 'UTF-8'
subject = u'Тема'
sender_addr = 'mail@domain.com'
sender_pass = 'XXX'
sender_name = u'Отправитель'
msg_body = u"""
Сообщение
"""
party = ['dmitryzvada@gmail.com',]
# mail prepare
subject = Header(unicode(subject), charset)
sender_name = str(Header(unicode(sender_name), charset))
sender = formataddr((sender_name, sender_addr))
mailer = smtplib.SMTP('mail.domain.com', 587)
mailer.login(sender_addr, sender_pass)
# do things
for email in party:
    body = msg_body
    msg = MIMEText(body.encode(charset), 'plain', charset)
    msg['Subject'] = subject
    msg['From'] = sender
    msg['To'] = email
    mailer.sendmail(sender, [email], msg.as_string())