If the error
"ERROR! unexpected parameter type in action: <class 'ansible.parsing.yaml.objects.AnsibleSequence'>" appears when running a role implies there is issue with the playbook. Mostly the playbook has been written in standalone mode and not as running inside a role. Playbook should not contain task, hosts and other parameters. Just the name of the task and the task parameters. This should fix the issue.
For example, a playbook file will look like below.
---
- shell: ls -la
register: shell_result
- debug:
var: shell_result.stdout_lines
...
And corresponding role file is:
---
- name: list task role
hosts: localhost
user: root
become: yes
become_user: root
roles:
- ls
...
