SectionData.php

<?php

namespace Drupal\layout_builder\Plugin\DataType;

use Drupal\Core\StringTranslation\TranslatableMarkup;
use Drupal\Core\TypedData\Attribute\DataType;
use Drupal\Core\TypedData\TypedData;
use Drupal\layout_builder\Section;

/**
 * Provides a data type wrapping \Drupal\layout_builder\Section.
 *
 * @internal
 *   Plugin classes are internal.
 */
class SectionData extends TypedData {
  
  /**
   * The section object.
   *
   * @var \Drupal\layout_builder\Section
   */
  protected $value;
  
  /**
   * {@inheritdoc}
   */
  public function setValue($value, $notify = TRUE) {
    if (is_array($value)) {
      $value = Section::fromArray($value);
    }
    if ($value && !$value instanceof Section) {
      throw new \InvalidArgumentException(sprintf('Value assigned to "%s" is not a valid section', $this->getName()));
    }
    parent::setValue($value, $notify);
  }

}