trying to query by extras in ckan pages actions

actions.py

def _pages_list(context, data_dict):
    print('data_dict')
    print(data_dict)
    search = {}
    org_id = data_dict.get('org_id')
    ordered = data_dict.get('order')
    order_publish_date = data_dict.get('order_publish_date')
    page_type = data_dict.get('page_type')
    private = data_dict.get('private', True)
    if ordered:
        search['order'] = True
    if page_type:
        search['page_type'] = page_type
    if order_publish_date:
        search['order_publish_date'] = True
    if not org_id:
        search['group_id'] = None
        try:
            p.toolkit.check_access('ckanext_pages_update', context, data_dict)
            if not private:
                search['private'] = False
        except p.toolkit.NotAuthorized:
            search['private'] = False
    else:
        group = context['model'].Group.get(org_id)
        user = context['user']
        member = authz.has_user_permission_for_group_or_org(
            group.id, user, 'read')
        search['group_id'] = org_id
        if not member:
            search['private'] = False

    schema = default_pages_schema()
    items = ['title', 'content', 'name', 'private',
             'order', 'page_type', 'publish_date']

    extras = {}
    extra_keys = set(schema.keys()) - set(items + ['id', 'created'])
    for key in extra_keys:
        if key in data_dict:
            extras[key] = data_dict.get(key)
    search['extras'] = json.dumps(extras)
    search['extras'] = u'{"add_to_home_page": true}'
    print('search is', search)
    out = db.Page.pages(**search)
    out_list = []