problems with mimify.mime_encode_header

[Egor Duda]

I'm trying to use mimify module and have a problem with
mime_encode_header function. Below is the testcase

#!/usr/bin/python
# -*- coding: utf-8 -*-

import mimify

mimify.CHARSET = 'utf-8'

print mimify.mime_encode_header('Subject: тест а.\n');

Тhe output is:
Subject: =?utf-8?Q?=D1=82=D0=B5=D1=81=D1=82?= а.

Please note that the last character (before dot) is not quoted, and
resulting string is not 8bit clean.

Is it incorrect behavior, or i'm calling mime_encode_header in a way
it's not supposed to be called?

egor