ansible/test/samples/with_flattened.yml

- hosts: localhost
  connection: local
  gather_facts:
  vars:
    list_a:
    - ['foo', 'bar']
    list_b:
    - [['bam', 'baz']]
  tasks:
  - debug: msg="item is {{item}}"
    with_flattened:
    - list_a
    - list_b