No attribute classroom in libre_infra.ec2

[startx-fk]

TASK [infra : aws : provision : Create 2 students environments] *****************************************************
included: /usr/local/lib/libre-ansible/roles/infra/tasks/aws/provision/instance.yml for localhost
included: /usr/local/lib/libre-ansible/roles/infra/tasks/aws/provision/instance.yml for localhost

TASK [infra : aws : provision : instance : Create {{libre_infra.ec2.classroom|length|default(0)}} ec2 instances for student {{labenv}} {{student.name}}] ***
fatal: [localhost]: FAILED! => {"msg": "'dict object' has no attribute 'classroom'"}
	to retry, use: --limit @/usr/local/lib/libre-ansible/playbooks/infra-aws/provision.retry

PLAY RECAP **********************************************************************************************************
localhost                  : ok=62   changed=6    unreachable=0    failed=1   

  ERROR ! Playbook infra-aws/provision ended with error