code: private Document getCommentlessDocument(Document orig) {
          if (!XMLUnit.getIgnoreComments()) {
              return orig;
          }
          try {
              Transform commentStripper = XMLUnit.getStripCommentsTransform(orig);
              return commentStripper.getResultDocument();
          } catch (TransformerException e) {
              throw new XMLUnitRuntimeException(e.getMessage(), e.getCause());
          }
      }
docs: Removes all comment nodes if {@link XMLUnit#getIgnoreComments
  comments are ignored}.
  
  @param orig a document making up one half of this difference
  @return manipulated doc