System.Linq.Expressions.MethodCallExpression2.GetArgument C# (CSharp) Метод

        public override Expression GetArgument(int index)
        {
            switch (index)
            {
                case 0: return ReturnObject<Expression>(_arg0);
                case 1: return _arg1;
                default: throw new ArgumentOutOfRangeException(nameof(index));
            }
        }