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Issue description

The student guide suggests that with_items performs one-level flattening of its lists.

I tried to reproduce to show to my delegates, but I couldn't

Steps to reproduce:

---
- hosts: all
  gather_facts: false
  tasks:
    - set_fact:
        lista1: "{{ [1, 2, [3, 4, [5]], 6] }}"
        lista2: "{{ [7, 8, [9]] }}"

    - name: "with_items task"
      debug:
        msg: "{{ item }}"
      with_items: 
        - "{{ lista1 }}"
        - "{{ lista2 }}"

    - name: "loop task"
      debug:
        msg: "{{ item }}"
      loop: "{{ (lista1 | flatten) + (lista2 | flatten) }}" 

The playbook above shows how the first debug task (with_items task) does not iterate on a flat list, but the second does (loop task)

Workaround:

using loop keyword instead of with_items..

Expected result:

{}I would expect the student guide to be corrected on the paragraph:

"The with_items keyword combines these three lists into a single list containing the entries from all three lists. It automatically performs one-level flattening of its list"

or more context provided. Or a reference to an example and documentation attached to this issue, in the case that I'm wrong.