Test to see if ansible version supports switching the handler based on var

test_switch_handler.playbook

---
- hosts: balancer
  sudo: yes
  serial: 1

  vars:
    switch: False
    name_of_handler: "{{ 'call_this' if switch else 'call_that' }}"

  handlers:
    - name: call_this
      command: echo Switch is on

    - name: call_that
      command: echo Switch is off

    - name: not_set
      command: echo Not been set!

  tasks:
    - name: Test
      command: "echo Test {{name_of_handler}}"
      notify: "{{name_of_handler}}"