         return color
     }
     
-    private class func storeColorInCache(hexString: String, color: UIColor) {
+    private class func storeColorInCache(_ hexString: String, color: UIColor) {
         
         if UIColor.hexColorCache.keys.contains(hexString) {
             return // No work to do if it is already there.

    private class func clearColorCache() {
        UIColor.hexColorCache.removeAll()
    }
}

extension UIColor {
    
    // Convert a hex string to a UIColor object.
    class func colorFromHex(_ hexString:String) -> UIColor {
        
        func cleanHexString(_ hexString: String) -> String {
            
            var cleanedHexString = String()
            
            // Remove the leading "#"
            if(hexString[hexString.startIndex] == "#") {
                cleanedHexString = hexString.substring(from: hexString.index(hexString.startIndex, offsetBy: 1))
            }
            
            // TODO: Other cleanup. Allow for a "short" hex string, i.e., "#fff"
