/**
* Returns the ANSI sequence for the given syntactic element, or {@code null} if none.
*/
final String getAnsiSequence(final ElementKind key) {
final X364 color = map.get(key);
return (color != null) ? color.sequence() : null;
}
/**
* Returns an immutable copy of this set of colors, or {@code this} if this instance is already immutable.
*/