&gt;You&#x27;re talking about eliminating duplicates in a list right?<p>No, I&#x27;m talking about any atbitrary list processing operation. Some combination of map, fold, and filter, for example.<p>So, in order to do that in an Ansible playbook, I need to write a Python function to do it and use it in the YAML file as a filter because the DSL isn&#x27;t expressive enough to do it on its own. So... why wouldn&#x27;t I want to just use Python again?