ANSIBLE how to locate dict at host_vars file?

I try to master the work with dictionaries at ansible. When I include dict to playbook as at example all works like charm. But when I try to include vars block to my host_vars/myserv.yml file like this:

host_vars/myserv.yml <- There is wrong syntax don't use this example!

  vars:
    users:
      alice:
        name: Alice Appleworth
        telephone: 123-456-7890
      bob:
        name: Bob Bananarama
        telephone: 987-654-3210

playbook.yml

- name: "myserv"
  hosts: "myserv"
  gather_facts: yes
  remote_user: root

  tasks:

  - name: "Ping hosts"
    ping:
  
  roles:
   - {role: 'test-role'}

roles/test-role/task/main.yml

- name: Print phone records
  debug:
    msg: "User {{ item.key }} is {{ item.value.name }} ({{ item.value.telephone }})"
  loop: "{{ lookup('dict', users) }}"

I get an error:

FAILED! => {"msg": "An unhandled exception occurred while running the lookup plugin 'dict'. Error was a <class 'ansible.errors.AnsibleError'>, original message: with_dict expects a dict"}

So what I missed? I need to use some lookup option?

UPD: the trouble was pretty simple - just remove "vars:" line from host_vars file and all work's fine :).

Regards