      - parameter to: given `destination unit`.
      
      - returns: `amount` converted to `destination unit`.
+     
+     - author: Michal Konturek
      */
     func convert(amount: NSNumber, to: Unit) -> NSNumber
     

     - parameter amount: `amount` in the `current unit`.
     
     - returns: `amount` converted to a `base unit`.
     */
    public func convertToBaseUnit(amount: NSNumber) -> NSNumber {
        let converted = NSDecimalNumber(decimal: amount.decimalValue)

     - parameter to: `destination unit`.
     
     - returns: `amount` converted from a `source unit` to a `destination unit`.
     
     - author: Michal Konturek
     */
    public func convert(amount: NSNumber, from: Unit, to: Unit) -> NSNumber {
        let baseAmount = from.convertToBaseUnit(amount)
