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: group_linkable.rb
    path of file: ./repos/gitlabhq/app/services/concerns
    
    the code of the file until where you have to start completion: # frozen_string_literal: true

module GroupLinkable
  extend ActiveSuppor
    
  def execute
    return error('Not Found', 404) unless valid_to_create?

    build_link

    if link.save
      after_successful_save
      success(link: link)
    else
      error(link.errors.full_messages.to_sentence, 409)
    end