BB.BL.Constants.YouTubeApiKey C# (CSharp) Method

        public static string YouTubeApiKey()
        {
            string KEY = "YouTubeApiKey";
            string youtubeApiKey = ConfigurationManager.AppSettings[KEY];

            if (string.IsNullOrEmpty(youtubeApiKey))
            {
                return Environment.GetEnvironmentVariable(KEY);
            }

            return youtubeApiKey;
        }
    }

 public YouTubeTrackProvider()
 {
     youtubeService = new YouTubeService(new BaseClientService.Initializer
     {
         ApiKey          = Constants.YouTubeApiKey(),
         ApplicationName = Constants.YoutubeApplicationName
     });
 }