code: public static int findLabelColumn(MultipleObjectsBundle bundle) {
      for(int i = 0; i < bundle.metaLength(); i++) {
        if(TypeUtil.GUESSED_LABEL.isAssignableFromType(bundle.meta(i))) {
          return i;
        }
      }
      return -1;
    }
docs: Find the first "label-like" column (matching {@link TypeUtil#GUESSED_LABEL}
  ) in a bundle.
  
  @param bundle Bundle
  @return Column number, or {@code -1}.