public override BsonValue Render()
        {
            BsonValue renderedArgs;

            if (_args.Count == 1)
            {
                renderedArgs = _args[0].Render();
                if (renderedArgs.BsonType == BsonType.Array)
                {
                    renderedArgs = new BsonArray {
                        renderedArgs
                    };
                }
            }
            else
            {
                renderedArgs = new BsonArray(_args.Select(e => e.Render()));
            }
            return(new BsonDocument(_operator.Render(), renderedArgs));
        }
 public override BsonValue Render()
 {
     return(new BsonDocument(_operator.Render(), new BsonArray(_args.Select(e => e.Render()))));
 }