code: @Override
      public Map<String, Object> toSource() {
          Map<String, Object> sourceMap = new HashMap<>();
          if (createdAt != null) {
              addFieldToSource(sourceMap, "createdAt", createdAt);
          }
          if (updatedAt != null) {
              addFieldToSource(sourceMap, "updatedAt", updatedAt);
          }
          return sourceMap;
      }
docs: ======