code: @Override
      public void add(Difference difference) {
          if(ignorePaths == null) {
              list.add(difference);
          } else {
              String pathA = trimNonXmlElements(difference.getPathA());
              String pathB = trimNonXmlElements(difference.getPathB());
              if (ignorePaths.contains(pathA) || ignorePaths.contains(pathB)) {
                  // ignorable matched
                  if(ignorePaths.contains(pathA) && ignorePaths.contains(pathB)) {
                      // both sides contains an ignorable difference
                      return;
                  } else if(pathA.length() > 0 && ignorePaths.contains(pathB)) {
                      // B contains ignorable
                      difference = new Difference(difference.getPathA(), null, "Only in: " + getNameA());
                      list.add(difference);
                  } else if(ignorePaths.contains(pathA) && pathB.length() > 0) {
                      // A contains ignorable
                      difference = new Difference(null, difference.getPathB(), "Only in: " + getNameB());
                      list.add(difference);
                  }
              } else {
                  // no ignorable matched
                  list.add(difference);
              }
          }
      }
docs: Add a new difference to the report
  @param difference {@code Difference}