BPM approval condition if worker's current assignment supervisor is "user A"

Summary:

The client has a separate approval workflow for the direct reports of the Director. Can we create a condition in BPM that mentions the worker's line manager?

Such as:

Task.payload.Worker's Current Assignment.result.Assignment Supervisor == "person number of the line manager"

When I use the person number, I get an error "RUL-05720: data type mismatch for test "==": List == String". Is there another attribute I can use?

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