protected function isMultiValued(Node $node, $role) {
    $isMultiValued = false;
    $mapper = $node->getMapper();
    if ($mapper->hasRelation($role)) {
      $relation = $mapper->getRelation($role);
      $isMultiValued = $relation->isMultiValued();
    }
    return $isMultiValued;
  }