                 return nil
             }
             // Create the intersection set that is the values from the current group that are in this steps subset of data groups
-            let currentSet = currentGroups!.intersection(self.dataGroups)
+            let currentSet = Set(currentGroups!).intersection(self.dataGroups)
             // If there is no overlap then return nil
             guard currentSet.count > 0 else { return nil }
             // Otherwise, look for an answer that maps to the current set

        return []
    }
}

     Create an `ORKStepResult` from the given set of data groups.
     @return    Step result for this step.
     */
    public func stepResult(currentGroups: [String]?) -> ORKStepResult? {
        
        // Look for a current choice from the input groups
        let currentChoices: [Any]? = {
