public static void AddOperators()
 {
     try
     {
         Console.Write("enter no. of Operators you want to add : ");
         int n = Convert.ToInt32(Console.ReadLine());
         for (int i = 0; i < n; i++)
         {
             MobileOperator mobileOperator = new MobileOperator();
             Console.WriteLine("enter operator name ");
             mobileOperator.OperatorName = Console.ReadLine();
             Console.WriteLine("enter operator Rating ");
             mobileOperator.OperatorRating = Convert.ToDecimal(Console.ReadLine());
             business.AddOperator(mobileOperator);
         }
         Console.WriteLine("--------------------------");
         Console.WriteLine("mobile Operator added successfully");
         Console.WriteLine("--------------------------");
     }
     catch (InvalidData e)
     {
         Console.WriteLine("--------------------------");
         Console.WriteLine(e.Message);
         Console.WriteLine("--------------------------");
     }
     catch (RatingOverLoadedException e)
     {
         Console.WriteLine("--------------------------");
         Console.WriteLine(e.Message);
         Console.WriteLine("--------------------------");
     }
     catch (Exception e)
     {
         Console.WriteLine("--------------------------");
         Console.WriteLine(e.Message);
         Console.WriteLine("--------------------------");
     }
 }