class BlogItemDiffCallback(
    var oldBlogList: List<BlogPost>,
    var newBlogList: List<BlogPost>

): DiffUtil.Callback() {

  override fun areItemsTheSame(
      oldItemPosition: Int,
      newItemPosition: Int
  ): Boolean {
      return (oldBlogList.get(oldItemPosition).pk
              == newBlogList.get(newItemPosition).pk)
  }

  override fun getOldListSize(): Int {
      return oldBlogList.size
  }

  override fun getNewListSize(): Int {
      return newBlogList.size
  }

  override fun areContentsTheSame(
      oldItemPosition: Int,
      newItemPosition: Int
  ): Boolean {
      return (oldBlogList.get(oldItemPosition)
              == newBlogList.get(newItemPosition))
  }
}