- name: test with_flattened
  set_fact: "{{ item }}=flattened"
  with_flattened:
    - [ 'a__' ]
    - [ 'b__', ['c__', 'd__'] ]

- name: verify with_flattened results
  assert:
    that:
        - "a__ == 'flattened'"
        - "b__ == 'flattened'"
        - "c__ == 'flattened'"
        - "d__ == 'flattened'"