How to use the invenio.messages.gettext_set_language function in invenio

categories exist as sub-collections of 'cc'). The second option is
    preferred.

    @param categories: comma-separated list of journal categories that will be linked from this RSS. If 'all', use all. If empty, try to use current category.
    @param label: label of the RSS link
    @param rss_icon_url: if provided, display the RSS icon in front of the label
    @param rss_icon_width: if provided, declared width for the RSS icon
    @param rss_icon_height: if provided, declared height for the RSS icon
    @param cc: if provided, use as root collection for the journal, and ignore 'categories' parameter.
    @param css_class: CSS class of the RSS link.
    """
    args = parse_url_string(bfo.user_info['uri'])
    category_name = args["category"]
    journal_name = args["journal_name"]
    ln = bfo.lang
    _ = gettext_set_language(ln)


    if cc:
        categories = []
    elif categories.lower() == 'all':
        categories = get_journal_categories(journal_name)
    elif not categories and category_name:
        categories = [category_name]
    else:
        categories = categories.split(',')

    # Build the query definition for selected categories. If a
    # category name can a match collection name, we can simply search
    # in this collection. Otherwise we have to search using the query
    # definition of the category.
    # Note that if there is one category that does not match a

def tmpl_show_examples(self, collection_name, ln):
        "returns html with js controls for example searches"

      # load the right message language
        _ = gettext_set_language(ln)

        def get_example_search_queries(name):
            """Returns list of sample search queries for this collection.
            """
            res = run_sql("""SELECT example.body FROM example LEFT JOIN collection_example ON example.id=collection_example.id_example LEFT JOIN collection ON collection_example.id_collection=collection.id WHERE collection.name=%s ORDER BY collection_example.score""", (name,))
            return [query[0] for query in res]


        # Build example of queries for this collection
        example_search_queries = get_example_search_queries(collection_name)
        example_search_queries_links = [create_html_link(self.build_search_url(p=example_query,
                                                                               ln=ln,
                                                                               aas= 0,
                                                                               cc=collection_name),
                                                         {},
                                                         cgi.escape(example_query),

def tmpl_admin_configure_journal(self, ln, journal_name='', xml_config=None,
                                     action='edit', msg=None):
        """
        Display a page to change the settings of a journal. Also used to
        add a new journal.
        """
        out = ''
        _ = gettext_set_language(ln)
        journal_name_readonly = 'readonly="readonly" disabled="disabled"'
        journal_name_note = ''
        submit_button_label = _('Apply')
        if action == 'add':
            journal_name = ''
            journal_name_readonly = ''
            journal_name_note = 'Used in URLs. Choose it short and meaningful. This cannot be changed later'
            submit_button_label = _('Add')
        elif action in ['edit', 'editDone']:
            # Display navigation menu
            out += '''<table class="admin_wvar">
        <tbody><tr><th cellspacing="0" class="adminheaderleft" colspan="5">%(menu)s</th></tr>
        <tr>
        <td>0.&nbsp;<small><a href="administrate?journal_name=%(journal_name)s">Administrate</a></small>&nbsp;</td>
        <td>1.&nbsp;<small><a href="feature_record?journal_name=%(journal_name)s">Feature a Record</a></small>&nbsp;</td>
        <td>2.&nbsp;<small>Edit Configuration</small>&nbsp;</td></tr></tbody></table>

def perform_remove_alert(alert_name, id_query, id_basket, uid, ln=CFG_SITE_LANG):
    """perform_remove_alert: remove an alert from the database
    input:  alert name
            identifier of the query;
            identifier of the basket
            uid
    output: confirmation message + the list of alerts Web page"""
    # load the right language
    _ = gettext_set_language(ln)
    # security check:
    if not check_user_can_add_alert(uid, id_query):
        raise AlertError(_("You do not have rights for this operation."))
    # set variables
    out = ""
    if (None in (alert_name, id_query, id_basket, uid)):
        return out
    # remove a row from the alerts table: user_query_basket
    query = """DELETE FROM user_query_basket
               WHERE id_user=%s AND id_query=%s AND id_basket=%s"""
    params = (uid, id_query, id_basket)
    res = run_sql(query, params)
    if res:
        out += "The alert <b>%s</b> has been removed from your profile.<br><br>\n" % cgi.escape(alert_name)
    else:
        out += "Unable to remove alert <b>%s</b>.<br><br>\n" % cgi.escape(alert_name)

def get_format_template_attrs(filename):
    """
    Returns the attributes of the format template with given filename

    The attributes are {'name', 'description'}
    Caution: the function does not check that path exists or
    that the format element is valid.
    @param filename: the name of a format template
    @return: a structure with detailed information about given format template
    """
    _ = gettext_set_language(CFG_SITE_LANG)
    attrs = {}
    attrs['name'] = ""
    attrs['description'] = ""
    try:
        template_file = open("%s%s%s" % (CFG_BIBFORMAT_TEMPLATES_PATH,
                                         os.sep,
                                         filename))
        code = template_file.read()
        template_file.close()

        match = None
        if filename.endswith(".xsl"):
            # .xsl
            attrs['name'] = filename[:-4]
        else:
            # .bft

def tmpl_account_list_alerts(self, ln, alerts):
        """
        Displays all the alerts in the main "Your account" page

        Parameters:

          - 'ln' *string* - The language to display the interface in

          - 'alerts' *array* - The existing alerts IDs ('id' + 'name' pairs)
        """

        # load the right message language
        _ = gettext_set_language(ln)

        out = """<form method="post" action="../youralerts/list" name="displayalert">
                 %(you_own)s:
                <select name="id_alert">
                  <option value="0">- %(alert_name)s -</option>""" % {
                 'you_own' : _("You own the following alerts:"),
                 'alert_name' : _("alert name"),
               }
        for alert in alerts :
            out += """<option value="%(id)s">%(name)s</option>""" % \
                   {'id': alert['id'], 'name': cgi.escape(alert['name'])}
        out += """</select>
                &nbsp;<input value="%(show)s" type="submit" class="formbutton">
                </form>""" % {
                  'show' : _("SHOW"),
                }

def get_waiting_requests(req, request_id, print_data, ln=CFG_SITE_LANG):
    """
    Get all loans requests who are waiting.

    @type request_id:   integer.
    @param request_id:  identify the hold request. It is also the primary key
                        of the table crcLOANREQUEST.

    @type print_data:   string.
    @param print_data:  print requests information.

    @return:            list of waiting requests (on loan with hold).
    """

    _ = gettext_set_language(ln)

    if print_data == 'true':
        return print_pending_hold_requests_information(req, ln)

    elif request_id:
        db.update_loan_request_status(request_id,'cancelled')
        update_request_data(request_id)
        result = db.get_loan_request_by_status('waiting')

    else:
        result = db.get_loan_request_by_status('waiting')

    navtrail_previous_links = '<a class="navtrail">Admin Area' \
                              '</a>' % (CFG_SITE_URL,)

def format_element(bfo, detail='no'):
    """ Prints the data of a journal authority record in HTML. By default prints
    brief version.

    @param detail: whether the 'detailed' rather than the 'brief' format
    @type detail: 'yes' or 'no'
    """
    from invenio.messages import gettext_set_language
    _ = gettext_set_language(bfo.lang)    # load the right message language
    # return value
    out = ""
    # local function
    def stringify_dict(d):
        """ return string composed values in d """
        _str = ""
        if 'a' in d:
            _str += d['a']
        return _str or ''
    # brief
    main_dicts = bfo.fields('130%%')
    if len(main_dicts):
        main_dict = main_dicts[0]
        main = stringify_dict(main_dict)
        ##out += "<p>" + "<strong>" + _("Main %s name") % _("journal") + "</strong>" + ": " + main + "</p>"
        out += "<a href="&quot; +&quot;/record/&quot;+ str(bfo.recID) +&quot;?ln=&quot; + bfo.lang + &quot;" style="margin-top:0px;margin-bottom:0px">" + main + "</a>"

        @param buttons_verbiage_dict: language for the buttons
        @type buttons_verbiage_dict: dict
        '''
        session = get_session(req)
        personinfo = {}

        try:
            personinfo = session["personinfo"]
        except KeyError:
            return ""

        if 'ln' in personinfo:
            ln = personinfo["ln"]
        else:
            ln = CFG_SITE_LANG
        _ = gettext_set_language(ln)

        if not verbiage_dict:
            verbiage_dict = self._get_default_verbiage_dicts_for_admin(req)
        if not buttons_verbiage_dict:
            buttons_verbiage_dict = self._get_default_buttons_verbiage_dicts_for_admin(req)

        all_papers = webapi.get_papers_by_person_id(self.person_id,
                                                    ext_out=True)

        records = [{'recid': paper[0],
                    'bibref': paper[1],
                    'flag': paper[2],
                    'authorname': paper[3],
                    'authoraffiliation': paper[4],
                    'paperdate': paper[5],
                    'rt_status': paper[6],

def doctypelist(req, ln=CFG_SITE_LANG):
    """List all WebSubmit document types."""

    ln = wash_language(ln)
    _ = gettext_set_language(ln)
    uid = getUid(req)

    (auth_code, auth_msg) = check_user(req, 'cfgwebsubmit')
    if not auth_code:
        ## user is authorised to use WebSubmit Admin:
        body = perform_request_list_doctypes()
        return page(title       = "Available WebSubmit Document Types",
                    body        = body,
                    navtrail    = get_navtrail(ln),
                    uid         = uid,
                    lastupdated = __lastupdated__,
                    req         = req,
                    language    = ln)
    else:
        ## user is not authorised to use WebSubmit Admin:
        return page_not_authorized(req=req, text=auth_msg, navtrail=get_navtrail(ln))