앤서블 오류입니다! 'AnsibleUnicode' 객체에는 'keys' 속성이 없습니다.

처음으로 Ansible을 실행했는데 다음 오류가 발생했습니다.

root@raspberrypi:/opt/ansible# ansible-playbook -i /opt/ansible/hosts simple.yml 
ERROR! 'AnsibleUnicode' object has no attribute 'keys'
/opt/ansible/hosts:1: Expected key=value host variable assignment, got: juniper

콘텐츠 simple.yml:

---
- name: Verifying NETCONF
  hosts: juniper
  tasks: 
    - name: Verifying NETCONF
      wait_for: host={{ansible_ssh_host}} port=22

콘텐츠 hosts:

juniper ansible_connection=local juniper ansible_port=22 ansible_host=172.16.0.1 juniper_user=root juniper_passwd=Juniper.2015

어떤 제안이 있으십니까?