docs: @Override
      public int compare(ProposalPersonContract person1, ProposalPersonContract person2) {
          int retval = 0;
                 
          if (person1.isInvestigator() || person2.isInvestigator()) {
              if (person1.isPrincipalInvestigator() 
                      || person2.isPrincipalInvestigator()) {
                 if (person1.isPrincipalInvestigator()) {
                     retval--;
                 }
                 
                 if (person2.isPrincipalInvestigator()) {
                     retval++;
                 }
              }
          }
          
          if (retval == 0) {
              retval = massageOrdinalNumber(person1).compareTo(massageOrdinalNumber(person2));
          }
          
          if (retval == 0) {
              if (isNotBlank(person1.getFullName())) {
                  retval = person1.getLastName().compareTo(person2.getLastName());
              }
              else if (isNotBlank(person2.getLastName())) {
                  retval--; 
              }
          }
          
          LOG.info("retval = " + retval);
  
          return retval;
      }