Add nested translated repeaters to RainLab.Pages

Plugin.php

<?php 

    public function boot()
    {
        Event::listen('backend.form.extendFieldsBefore', function (\Backend\Widgets\Form $form) {
            $isStaticPage = $form->getController() instanceof \RainLab\Pages\Controllers\Index
                && $form->model instanceof \RainLab\Pages\Classes\Page;

            if ($isStaticPage && !$form->isNested) {
                $fields = Yaml::parse(<<<YAML
title:
    label: Title
    type: text
    span: full

blocks:
    label: Blocks
    type: repeater
    prompt: Add block
    form:
        fields:
            title:
                label: Title
                type: text
                span: full

            content:
                label: Content
                type: richeditor
                span: full
YAML
                );

                $form->secondaryTabs['fields'] = [
                        'viewBag[sections]' => [
                            'tab'      => 'Sections',
                            'type'     => 'repeater',
                            'form'     => ['fields' => $fields],
                            'prompt'   => 'Ajouter une section',
                            'cssClass' => 'secondary-tab ',
                        ],
                    ] + $form->secondaryTabs['fields'];

                $form->model->translatable[] = 'viewBag[sections]';
            }

        });
    }