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: jenkins_gather.rb
    path of file: ./repos/metasploit-framework/modules/post/multi/gather
    
    the code of the file until where you have to start completion: require 'nokogiri'
require 'base64'
require 'digest'
require 'openssl'
require 'sshkey'

class MetasploitModule < Msf::P
    
  def decrypt_key(master_key, hudson_secret_key)
    # https://gist.github.com/juyeong/081379bd1ddb3754ed51ab8b8e535f7c
    magic = '::::MAGIC::::'
    hashed_master_key = Digest::SHA256.digest(master_key)[0..15]
    intermediate = OpenSSL::Cipher.new('AES-128-ECB')
    intermediate.decrypt
    intermediate.key = hashed_master_key

    salted_final = intermediate.update(hudson_secret_key) + intermediate.final
    raise 'no magic key in a' if !salted_final.include?(magic)

    salted_final[0..15]
  end