                 resultString += "\n    Exclusive: \(exclusive)"
                 if !selectors.isEmpty {
                     resultString += "\n    Selectors:"
-                    resultString += selectors.map { selectorDict in
+                    let selectorStrings: [String] = selectors.map { selectorDict in
                         let selectorName = selectorDict[kCTFontFeatureSelectorNameKey as String] as? String
                         let selectorIsDefault = selectorDict[kCTFontFeatureSelectorDefaultKey as String] as? Bool ?? false
 

                            resultString += " (default)"
                        }
                        return resultString
                        }.reduce("") { $0 + "\n" + $1 }
                }
                return resultString
                }.reduce("") { $0 + "\n\n" + $1 }
        }

    }

        ///         and match any combination of its options.
        public func availableFontFeatures(includeIdentifiers includeIDs: Bool = false) -> String {
            let preamble = "Available font features of \(fontName)"
            let features: [String] = availableFeaturesDictionaries.map { featureDict in
                let featureName = featureDict[kCTFontFeatureTypeNameKey as String] as? String
                let exclusive = featureDict[kCTFontFeatureTypeExclusiveKey as String] as? Bool ?? false
                let selectors = featureDict[kCTFontFeatureTypeSelectorsKey as String] as? [FontFeatureDictionary] ?? []
