docs: public static String createAssignmentMessage(final String tagName,
              final AssignmentResult<? extends NamedEntity> result, final VaadinMessageSource i18n) {
          final StringBuilder formMsg = new StringBuilder();
          final int assignedCount = result.getAssigned();
          final int alreadyAssignedCount = result.getAlreadyAssigned();
          final int unassignedCount = result.getUnassigned();
          if (assignedCount == 1) {
              formMsg.append(i18n.getMessage("message.target.assigned.one", result.getAssignedEntity().get(0).getName(),
                      tagName)).append("<br>");
          } else if (assignedCount > 1) {
              formMsg.append(i18n.getMessage("message.target.assigned.many", assignedCount, tagName)).append("<br>");
  
              if (alreadyAssignedCount > 0) {
                  final String alreadyAssigned = i18n.getMessage("message.target.alreadyAssigned", alreadyAssignedCount);
                  formMsg.append(alreadyAssigned).append("<br>");
              }
          }
          if (unassignedCount == 1) {
              formMsg.append(i18n.getMessage("message.target.unassigned.one",
                      result.getUnassignedEntity().get(0).getName(), tagName)).append("<br>");
          } else if (unassignedCount > 1) {
              formMsg.append(i18n.getMessage("message.target.unassigned.many", unassignedCount, tagName)).append("<br>");
          }
          return formMsg.toString();
      }