code: protected final LocalDate estimateFromOtherEvents(
              final LocalDate localDate) {
          if (localDate != null) {
              return localDate;
          }
          final PersonAnalysisVisitor visitor = new PersonAnalysisVisitor();
          person.accept(visitor);
          for (final Attribute attr : visitor.getAttributes()) {
              final String dateString = getDate(attr);
              final LocalDate date = estimateFromEvent(attr, dateString);
              if (date != null) {
                  return date;
              }
          }
          return null;
      }
docs: Try other lifecycle events.
  
  @param localDate if not null we already have a better estimate
  @return estimate