Without the added `return {}`, calling route53.list_tags_for_resource when called with a ResourceId of a resource without any tags would result in the error: jinja2.exceptions.UndefinedError: 'None' has no attribute 'items' Because the LIST_TAGS_FOR_RESOURCE_RESPONSE was given None instead of empty dict. This now allows list_tags_for_resource to be called without issue on tag-less resources.