I am doing somthing silly with syntax but what?

reuslts.txt

  TASK [debug] *******************************************************************
       ok: [localhost] => {
           "omeka_cache": [
        {
            "app": "/opt/omeka/apps"
        }, 
        {
            "plugins": "/opt/omeka/plugins"
        }, 
        {
            "theme": "/opt/omeka/themes"
        }
           ]
       }
       
       TASK [download applications files] *********************************************
       fatal: [localhost]: FAILED! => {"failed": true, "msg": "'list object' has no attribute 'app'"}

role.yml

- name: debug
  debug: var=omeka_cache
- name: download applications files
  unarchive: 
    src:  "http://omeka.org/files/omeka-{{ inst.value.version }}.zip"
    copy: no
    dest: "{{ omeka_cache.app }}"

var.yml

omeka_cache_base: /opt/omeka
  omeka_cache:
  - app: "{{ omeka_cache_base }}/apps"
  - plugins: "{{ omeka_cache_base }}/plugins"
  - theme: "{{ omeka_cache_base }}/themes"