private string GetParameterValue(string parameterKey, StoppedParameter parameter)
 {
     switch (parameterKey)
     {
         case "name":
             return parameter.Name;
         case "password":
             return parameter.YellowPagesParameters.Single(x => x.Key == "password").Value;
         case "result_format":
             return "json";
         default:
             throw new ArgumentException();
     }
 }
 public Task OnStopedAsync(StoppedParameter parameter)
 {
     var nvc = new NameValueCollection();
     foreach (var param in StopParameters)
     {
         nvc.Add(param, GetParameterValue(param, parameter));
     }
     return Post(StopUrl, nvc);
 }