ansible example getting item from previous iteration of loop

test.yml

- hosts: localhost
  connection: local
  gather_facts: no
  vars:
    mylist:
    - a
    - b
    - c
  tasks:
    - debug:
        msg: '{{ ansible_loop.previtem|default("") }}{{ item }}'
      loop: '{{ mylist }}'
      loop_control:
        extended: yes