FirstArgumentMustBeCallSite() статический приватный Метод

ArgumentException with message like "First argument of delegate must be CallSite"
static private FirstArgumentMustBeCallSite ( ) : Exception
Результат System.Exception
        private static MethodInfo GetValidMethodForDynamic(Type delegateType)
        {
            var method = delegateType.GetMethod("Invoke");
            var pi     = method.GetParametersCached();

            if (pi.Length == 0 || pi[0].ParameterType != typeof(CallSite))
            {
                throw Error.FirstArgumentMustBeCallSite();
            }
            return(method);
        }