code: @Override
      public Collection<PersonDocument> findByFileAndSurname(
              final String filename, final String surname) {
          if (filename == null || surname == null) {
              return Collections.emptyList();
          }
          final Query searchQuery =
                  new Query(Criteria.where("surname").is(surname)
                          .and("filename").is(filename));
          final List<PersonDocumentMongo> personDocuments =
                  mongoTemplate.find(searchQuery, PersonDocumentMongo.class);
          createGedObjects(personDocuments);
          return copy(personDocuments);
      }
docs: {@inheritDoc}