{% if not_exist %}
{% if a_ident %}
  --> shoud not display '{{ a_ident }}'
{% else %}
  --> shoud not display '{{ a_ident }}' too
{% endif %}
{% else %}
{% if a_ident %}
  --> shoud display '{{ a_ident }}' here
{% else %}
  --> shoud not display '{{ a_ident }}' in this case
{% endif %}
{% endif %}
TOTO