Kaip padaryti vertima su kintamaisiai

import locale
import gettext
import os
current_locale = 'en_US'
locale_path = 'lang/'
language = gettext.translation ('proj', locale_path, [current_locale] )
_text = language.gettext
print _text('reik1')
zzz = _text('reik2 %(username)s') % {'username': "aaa"}
print zzz


proj.po
msgid "reik1"
msgstr "cia tokia reiksme"

msgid "reik2 %(username)s"
msgstr "cia tokia reiksme, %(username)s"

>>>zzz = _text('reik2 %(username)s') % {'username': "aaa"} - si eilute 
>>>nevercia