Splitting in Jinja2/Ansible

test_split_jinja_ansible.yml

---
- name: Test split
  hosts: localhost
  gather_facts: false
  vars:
    - facter_blockdevices: "sda,sdb,sdc,sdd,sde,sdf"
  tasks:
    - name: Let's split
      debug: var=item
      with_items: "facter_blockdevices.split(',')"

I get the following output when i try this. Please help.

TASK [Let's split] ************************************************************************************************************************************************************
ok: [localhost] => (item=None) => {}
ok: [localhost] => (item=None) => {}
ok: [localhost] => (item=None) => {}
ok: [localhost] => (item=None) => {}
ok: [localhost] => (item=None) => {}
ok: [localhost] => (item=None) => {}