---
- name: Get subnet
  azure_rm_subnet_info:
    ad_user: "{{ azure_ad_user | default(omit) }}"
    password: "{{ azure_password | default(omit) }}"
    subscription_id: "{{ subnet.azure_subscription_id | default(lookup('env', 'AZURE_SUBSCRIPTION_ID')) }}"
    client_id: "{{ azure_client_id | default(lookup('env', 'AZURE_CLIENT_ID')) }}"
    secret: "{{ azure_secret | default(lookup('env', 'AZURE_SECRET')) }}"
    tenant: "{{ azure_tenant | default(lookup('env', 'AZURE_TENANT')) }}"
    resource_group: "{{ subnet.resource_group }}"
    virtual_network_name: "{{ subnet.virtual_network_name }}"
    name: "{{ subnet.name | default(omit, true) }}"
  register: azure_subnet_facts

- name: Print subnet
  debug:
    var: azure_subnet_facts.subnets
...