Django Template: How to concatenate strings and django-template variables

django-template-concatenate-string.html

{% with "shop/"|add:shop_name|add:"/base.html" as template %} 
  {% include template %} 
{% endwith %} 


{% with "Create "|add:org_name|add:"'s Website" as website_form_name %} 
  {% include 'backend/snippets/form.html' with form_name=website_form_name %} 
{% endwith %}