Project macro not returning Dataset selection

Hello,

I am trying to develop a macro that can be run from the project Macros menu. When I specify a DATASET parameter, the macro displays a list of datasets but doesn't return the value selected. Any ideas?

Here is the runnable.json file:

{
    "meta": {
        "label": "Custom runnable test-dataset-param",
        "description": "Test dataset parameter",
        "icon": "icon-puzzle-piece"
    },
    "impersonate": false,
    "params": [
        {
            "name": "source_dataset",
            "label": "Source Dataset",
            "type": "DATASET",
            "description": "Specify the dataset",
            "mandatory": true
        }
    ],
    "permissions": [],
    "resultType": "HTML",
    "resultLabel": "Result label",
    "extension": "txt",
    "mimeType": "text/plain",
    "macroRoles": [{"type": "PROJECT_MACROS"}]
}

For this test, in the runnable.py file I'm simply returning the whole config, i.e.: return self.config

I realize I can make this macro available in the dataset actions in the flow. That works. Maybe that's what I'll need to do but thought I'd explore whether the project macro approach could work as well as this would be my preferred approach.

Thanks,

Marlan