public void visit(MetricsAndOperator metricsAndOperatorPredicate)
 {
     if (metricsAndOperatorPredicate != null)
     {
         xmlWriter.WriteStartElement("And", "http://s3.amazonaws.com/doc/2006-03-01/");
         foreach (MetricsFilterPredicate operand in metricsAndOperatorPredicate.Operands)
         {
             operand?.Accept(this);
         }
         xmlWriter.WriteEndElement();
     }
 }
 public void visit(MetricsAndOperator metricsAndOperatorPredicate)
 {
     if (metricsAndOperatorPredicate != null)
     {
         xmlWriter.WriteStartElement("And", "http://s3.amazonaws.com/doc/2006-03-01/");
         foreach (var predicate in metricsAndOperatorPredicate.Operands)
         {
             if(predicate!=null)
                 predicate.Accept(this);
         }
         xmlWriter.WriteEndElement();
     }
 }