     
     //MARK: internal
     
-    static func factoryDuration(
-        travels:[DPlanTravel]) -> DPlanTravelDuration
+    static func factoryDuration(travels:[DPlanTravel]) -> DPlanTravelDuration
     {
-        let totalDuration:TimeInterval = factoryTotalDuration(
-            travels:travels)
-        let duration:DPlanTravelDuration = factoryDuration(
-            totalDuration:totalDuration)
+        let totalDuration:TimeInterval = factoryTotalDuration(travels:travels)
+        let duration:DPlanTravelDuration = factoryDuration(totalDuration:totalDuration)
         
         return duration
     }

        return duration
    }
    
    private static func factoryDuration(
        totalDuration:TimeInterval) -> DPlanTravelDuration
    {
        let duration:DPlanTravelDuration
        
        if totalDuration > kSecondsInDay
        {
            duration = factoryDays(
                duration:totalDuration)
        }
        else if totalDuration > kSecondsInHour
        {
            duration = factoryHours(
                duration:totalDuration)
        }
        else if totalDuration > kSecondsInMinute
        {
            duration = factoryMinutes(
                duration:totalDuration)
        }
        else
        {
            duration = factorySeconds(
                duration:totalDuration)
        }
        
        return duration
    }
    
    private static func factoryDays(
        duration:TimeInterval) -> DPlanTravelDuration
    {
        let days:TimeInterval = duration / kSecondsInDay
        let model:DPlanTravelDuration = DPlanTravelDuration(
            type:DPlanTravelDurationType.days,
            amount:days)

        return model
    }
    
    private static func factoryMinutes(duration:TimeInterval) -> DPlanTravelDuration
    {
        let minutes:TimeInterval = duration / DPlanTravelDuration.Constants.secondsInMinute
        
        let model:DPlanTravelDuration = DPlanTravelDuration(
            type:DPlanTravelDurationType.minutes,
            amount:minutes)
