code: Integer addHighlight(@NonNull View view, @NonNull String attribute, @ColorInt int colorId) {
          final Pair<Integer, String> pair = new Pair<>(view.getId(), attribute);
          highlightedAttributes.add(pair);
          return attributeColors.put(pair, colorId);
      }
docs: Enables highlighting for this view/attribute pair.
  
  @param attribute the attribute to color.
  @param colorId   a {@link ColorInt} to associate with this attribute.
  @return the previous color associated with this attribute or {@code null} if there was none.