<?php

class NovelList extends Illuminate\Support\Collection
{

  public function __construct($items = [])
  {
    $not_allow_items = array_filter($this->getArrayableItems($items), function ($item){
      return !($item === null || $item instanceof Novel);
    });

    if (!empty($not_allow_items)) {
      throw new InvalidArgumentException('NovelList required only array of nullable Novel.');
    }

    parent::__construct($items);
  }

}