private function addCustomStylesSection(NodeBuilder $ezRichTextNode)
    {
        return $ezRichTextNode
                ->arrayNode('custom_styles')
                // workaround: take into account Custom Styles names when merging configs
                ->useAttributeAsKey('style')
                ->arrayPrototype()
                    ->children()
                        ->scalarNode('template')
                            ->defaultNull()
                        ->end()
                        ->scalarNode('inline')
                            ->defaultFalse()
                        ->end()
                    ->end()
                ->end()
            ->end()
        ;
    }