How to create translation to "timesince" value ? (template tag)

Question

I review docs but I am lost... some problem with it:

{% load i18n %}
{% blocktrans %}
{{ wpis.entry.lastChangeDate|timesince }}
{% endblocktrans %}

Raise:

`KeyError: u'wpis.entry.lastChangeDate | timesince'`

Of course, without blocktrans all works fine.

So, what is simples way to translate few words? (I am interesting polish lang, minutes -> minut, hours -> godzin, etc) I will be thankful for clear example.

EDIT: in my .po file i have now:

#: templates/part.html:37 
#, python-format 
msgid "" 
"\n" 
"%(lastChangeDate)s\n" 
msgstr ""

and i don't see anything about var in docs... now i would do:

msgid "hours" 
msgstr "godzin"

etc and bind it to my var (above example don't work...)

Answer 1

{% load i18n %}
{% blocktrans with wpis.entry.lastChangeDate|timesince as lastChangeDate %}
{{ lastChangeDate }}
{% endblocktrans %}

See http://docs.djangoproject.com/en/dev/topics/i18n/#in-template-code for more info.