         }
     }
     
+    /// Fourth interval family.
     public class Fourth: EnumFamily {
+        
+        /// Diminished Fourth interval.
         public static let Diminished: EnumKind = .DiminishedFourth
+        
+        /// Perfect Fourth interval.
         public static let Perfect: EnumKind = .PerfectFourth
+        
+        /// Augmented Fouth interval.
         public static let Augmented: EnumKind = .AugmentedFourth
         
         public override class var members: [EnumKind] {

        11: [.MajorSeventh, .DiminishedUnison],
    ]
    
    public class Unison: EnumFamily {
        public static let Diminished: EnumKind = .DiminishedUnison
        public static let Perfect: EnumKind = .PerfectUnison
        public static let Augmented: EnumKind = .AugmentedUnison
        
        public override class var members: [EnumKind] { return [Perfect, Augmented] }

        }
    }
    
    /// Seventh interval family.
    public class Seventh: EnumFamily {
        
        /// Diminished Seventh interval.
        public static let Diminished: EnumKind = .DiminishedSeventh
        
        /// Minor Seventh interval.
        public static let Minor: EnumKind = .MinorSeventh
        
        /// Major Seventh interval.
        public static let Major: EnumKind = .MajorSeventh
        
        /// Augmented Seventh interal.
        public static let Augmented: EnumKind = .AugmentedSeventh
        
        public override class var members: [EnumKind] {
            return [Diminished, Minor, Major, Augmented]
        }
        
        public override class func kind(
            coarseAdjustmentLower: PitchSpelling.CoarseAdjustment,
