Ansible playbook that checks if there is less than 95% free disk space

checkdiskspaceall.yml

# checkdiskspaceall.yml
---
- hosts: zcoin_masternodes
  vars_files: vault.yml
  become: yes
  become_method: sudo
  gather_facts: yes
  tasks:
     - name: Collect only facts about hardware
       setup:
         gather_subset:
           - 'hardware'

     - name: Test for available disk space
       setup: filter=ansible_mounts
       
     - name: Ensure that free space on the tested volume is greater than 15%
       assert:
         that:
           - mount.size_available > mount.size_total|float * 0.05
         msg: Disk space has reached 95% threshold
       vars:
         mount: "{{ ansible_mounts | selectattr('mount','equalto',item.mount) | list | first }}"
       with_items:
         - "{{ ansible_mounts }}"

This playbook requires:

• ssh keys uploaded to the hosts for ansible to log in
• ansible to be installed on the controlling machine (can be your local machine or another server)
• a hosts file on the controlling machine that specifies the IP addresses, ssh ports and login usernames of the hosts / nodes
• an ansible vault file on the controlling machine with the encrypted passwords that are needed for sudo

Command I use to run this playbook with ansible:

$ sudo ansible-playbook -i hosts --ask-vault-pass checkdiskspaceall.ylm -vv

how can I check only / partition ?