private @Nullable Character getPreferredQuoteStyle() {
    final ASTNode value = XmlChildRole.ATTRIBUTE_VALUE_FINDER.findChild(myAttribute.getNode());
    String currentValue = notNull(doIfNotNull(value, ASTNode::getText), "");
    return currentValue.startsWith("'") ? Character.valueOf('\'') : currentValue.startsWith("\"") ? Character.valueOf('"') : null;
  }
private @Nullable Character getPreferredQuoteStyle()