form_template.html.twig

{% form_theme form _self %}
{% block _wowo_bundle_newsletterbundle_newslettertype_mailing_body_widget %}
    {{ form_widget(form, { 'attr': {'class': 'tinymce'}}) }}
{% endblock %}

    <form action="" method="post" {{ form_enctype(form) }} >
        {{ form_widget(form) }}
        <input type="submit" value="{% trans %}Send mailing{% endtrans %}"/>
    </form>