failure to parse `environment`

I am running

`

  • name: Install logstash {{ logstash_apt_version }}
    apt:
    pkg: “logstash={{ logstash_apt_version }}”
    state: present
    force: “{{ logstash_apt_force | default(false) }}”
    environment: “{{ logstash_environment | default(omit) }}”
    register: apt_logstash
    notify: restart logstash
    `

Where in this case environment is not defined, and I get this warning. Why would this be?

`
TASK [logstash : Install logstash 1:6.5.2-1] ************************************************************************************************************************************************************************************************
[WARNING]: could not parse environment value, skipping: [u’{{ logstash_environment | default(omit) }}']

changed: [10.0.198.55]

`