(Laravel) How to delete multiple models including optional relationships?

Schema::table('comments', function (Blueprint $table) {
    ...
    $table->unsignedInteger('posts_id');
    $table->foreign('posts_id')
          ->references('id')
          ->on('posts')
          ->onDelete('cascade');
});

public function delete()
{
    $this->images()->delete();
    $this->comments()->delete();

    return parent::delete(); 
}

Post::findMany($ids)->each(function ($item) {
        $item->delete();
    });

class Post extends Eloquent
{
    public function comments()
    {
        return $this->hasMany(Comment::class);
    }

    public function images()
    {
        return $this->hasMany(Images::class);
    }

    public static function boot() {
        parent::boot();

        static::deleting(function($post) { 
                $post->comments()->delete();
                $post->images()->delete();
                // or call another method here after you declare above
        });
    }
}

$post = Post::find($id);
$post->delete();