Using explicit string arrays as referenceValue in AWS Flexmatch

For Flexmatch rules, is it possible to use an explicit string array as a referenceValue, such as:

{
     "name": "P1CanJungle",
     "description": "Player 1 can play Jungle",
     "type": "collection",
     "operation": "reference_intersection_count",
     "measurements": ["flatten(teams[P1].players.attributes[roles])"],
     "referenceValue": ["jungle"],
     "minCount": 1
},

This is intended for use in a compound rule, where we make an exception and allow specific pairs of roles if their roles are identical and thus normally not permitted as a match.

I've tried a variety of syntaxes on the referenceValue, but they all result in "Collection rule encountered a measurement which was not a list of string lists; location: rules section: array index=0: P1CanTop".

Thanks!

EDIT - Ahhh it seems I cannot read thoroughly enough - you can use the "contains" operation on collections for this.