using carry_over_tag in Deluge

using carry_over_tag in Deluge

Hi all

Trying to use some deluge to convert some leads and want to carry over the tags that exist on the Lead record to the account/contact records. I see in the help that there is a carry_over_tags section in the sample json but can't seem to get this to work having tried various map methods. Has anyone got an example of how to do it? I've seen the URL method but was wondering if there's a way of doing it with a map. 

Thanks

Gav