/// <summary>
        /// A method used to search through the database in order to find
        /// an air conditioner by manufacturer and model
        /// </summary>
        /// <param name="manufacturer">The manufacturer you would be searching for</param>
        /// <param name="model"> The model that you would be searching for</param>
        /// <returns>returns a string with the specifications of the found device</returns>
        public string FindAirConditioner(string manufacturer, string model)
        {
            IAirConditioner airConditioner = database.GetAirConditioner(manufacturer, model);

            if (airConditioner == null)
            {
                throw new NonExistantEntryException();
            }
            return(airConditioner.ToString());
        }
 public void FindAirConditioner(string manufacturer, string model)
 {
     try
     {
         IAirConditioner airConditioner = data.GetAirConditioner(manufacturer, model);
         writer.WriteLine(airConditioner.ToString());
     }
     catch (NullReferenceException)
     {
         writer.WriteLine("The specified entry does not exist.");
     }
 }
        /// <summary>
        /// A method that finds an Air Conditioner in the database from a given manufacturer and model.
        /// </summary>
        /// <param name="manufacturer">The Manufacturer of the searched air conditioner.</param>
        /// <param name="model">The model of the searched air conditioner.</param>
        /// <returns>If the air conditioner exists in the database returns it's string represention, othrerwise it throws an appropriate exception.</returns>
        public string FindAirConditioner(string manufacturer, string model)
        {
            IAirConditioner airConditioner = this.Database.AirConditioners.GetItem(manufacturer, model);

            return(airConditioner.ToString());
        }