def do_translate(parser, token):
    class TranslateParser(TokenParser):
        def top(self):
            value = self.value()

            # Backwards Compatiblity fix:
            # FilterExpression does not support single-quoted strings,
            # so we make a cheap localized fix in order to maintain
            # backwards compatibility with existing uses of ``trans``
            # where single quote use is supported.
            if value[0] == "'":
                pos = None
                m = re.match("^'([^']+)'(\|.*$)",value)
                if m:
                    value = '"%s"%s' % (m.group(1).replace('"','\\"'),m.group(2))
                elif value[-1] == "'":
                    value = '"%s"' % value[1:-1].replace('"','\\"')

            if self.more():
                if self.tag() == 'noop':
                    noop = True
                else:
                    raise TemplateSyntaxError("only option for 'trans' is 'noop'")
            else:
                noop = False
            return (value, noop)
    value, noop = TranslateParser(token.contents).top()
    return TranslateNode(parser.compile_filter(value), noop)
This will mark a string for translation and will
dataset/ETHPy150Open AppScale/appscale/AppServer/lib/django-1.3/django/templatetags/i18n.py/do_translate