code: private void validateOrderByAttribute(String attributeName)
      {
  
          if ((!nameToAggregateAttributeMap.containsKey(attributeName)) && (!nameToGroupByAttributeMap.containsKey(attributeName)))
          {
              throw new MithraBusinessException("Aggregate list cannot be order by  attribute with name: " + attributeName + ".\n" +
                      "An AggregateList can only be ordered by an attribute which is either a AggregateAttribute or a GroupByAttribute");
          }
  
      }
docs: The attribute to group by should be either a aggregate attribute or a group by attribute.
  
  @param attributeName