[users_and_groups] warning in user's creation (to be error in ansible 2.14)

ok: [alfa.cielito.uy] => {
    "current_user_creation": {
        "append": true,
        "changed": true,
        "comment": "root",
        "failed": false,
        "group": 0,
        "home": "/root",
        "move_home": false,
        "name": "root",
        "password": "NOT_LOGGING_PASSWORD",
        "shell": "/bin/bash",
        "state": "present",
        "uid": 0,
        "warnings": [
            "'append' is set, but no 'groups' are specified. Use 'groups' for appending new groups.This will change to an error in Ansible 2.14."
        ]
    }
}

ver el warning, conviene filtrar groups/append de manera correcta.