public Pair<Color, Double> getColor(@Nullable String s) {
    if (s == null) {
      return Pair.create(null, -1.0);
    }
    int startOffset = StringUtil.startsWithChar(s, '#') ? 1 : 0;
    Color color = ColorUtil.fromHex(s.substring(startOffset, startOffset + 6), null);
    double alpha = s.length() > 7 ? parseAlpha(s.substring(startOffset + 6)) : -1;
    return Pair.create(color, alpha);
  }
public Pair<Color, Double> getColor(@Nullable String s)