You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: forum_post_response.rb
    path of file: ./repos/coursemology2/app/models/course/assessment/answer
    
    the code of the file until where you have to start completion: # frozen_string_literal: true
class Course::Assessment::Answer::ForumPostResponse < ApplicationRecord
  acts_as :answer, class_name: Course::Assessment::Answer.name

  # A post pack is a group of 4 object
    
  def compute_parent(selected_post)
    return unless selected_post.parent_id

    parent = Course::Discussion::Post.find_by(id: selected_post.parent_id)
    selected_post.is_parent_deleted = parent.nil?
    # a post with a deleted parent will have is_parent_updated = nil
    selected_post.is_parent_updated = parent ? later?(parent.updated_at, selected_post.parent_updated_at) : nil
    selected_post.parent_creator = User.find_by(id: selected_post.parent_creator_id)
  end