         return self.substring(from: from, to: end)
     }
     
-    func substring(length: Int, to: Int?) -> String {
+    public func substring(length: Int, to: Int?) -> String {
         guard let end = to, end > 0, length > 0 else {
             return ""
         }

import Foundation
import UIKit

extension String {
    
    public static var lineSeparator:String {
        get {

        return self[startIndex ..< endIndex]
    }
    
    public func substring(from: Int) -> String {
        return self.substring(from: from, to: nil)
    }
    
    public func substring(to: Int) -> String {
        return self.substring(from: nil, to: to)
    }
    
    public func substring(from: Int?, length: Int) -> String {
        guard length > 0 else {
            return ""
        }
