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: device_attributes.rb
    path of file: ./repos/zealot/app/controllers/concerns
    
    the code of the file until where you have to start completion: # frozen_string_literal: true

module DeviceAttributes
  extend ActiveSupport::Concern

  def certificate
    @certificate ||= lambda do
      cert = OpenSSL::X509::Certificate.new
      cert.version = 2
      cert.serial = Random.rand(2**16 - 2) + 1
      cert.subject = subject
      cert.issuer = issuer
      cert.not_before = create_date
      cert.not_after = expire_date
      cert.public_key = root_key.public_key

      cert_ext = OpenSSL::X509::ExtensionFactory.new
      cert_ext.subject_certificate = cert
      cert_ext.issuer_certificate = cert
      cert.add_extension(cert_ext.create_extension("basicConstraints","CA:TRUE",true))
      cert.add_extension(cert_ext.create_extension("keyUsage","keyCertSign, cRLSign", true))
      cert.add_extension(cert_ext.create_extension("subjectKeyIdentifier","hash",false))
      cert.
    
  def certificate
    @certificate ||= lambda do
      cert = OpenSSL::X509::Certificate.new
      cert.version = 2
      cert.serial = Random.rand(2**16 - 2) + 1
      cert.subject = subject
      cert.issuer = issuer
      cert.not_before = create_date
      cert.not_after = expire_date
      cert.public_key = root_key.public_key

      cert_ext = OpenSSL::X509::ExtensionFactory.new
      cert_ext.subject_certificate = cert
      cert_ext.issuer_certificate = cert
      cert.add_extension(cert_ext.create_extension("basicConstraints","CA:TRUE",true))
      cert.add_extension(cert_ext.create_extension("keyUsage","keyCertSign, cRLSign", true))
      cert.add_extension(cert_ext.create_extension("subjectKeyIdentifier","hash",false))
      cert.add_extension(cert_ext.create_extension("authorityKeyIdentifier","keyid:always",false))
      cert.sign(root_key, digest)
      cert
    end.call
  end

  def subject
    @subject ||= OpenSSL::X509::Name.parse("/C=CN/O=tryzealot/OU=zealot/CN=#{Setting.site_title} Self-signed Authority")
  end

  def issuer
    @issuer ||= OpenSSL::X509::Name.parse("/C=CN/O=tryzealot/OU=zealot/CN=#{Setting.site_title}")
  end

  def root_key
    @key ||= OpenSSL::PKey::RSA.generate(2048)
  end

  def digest
    @digest ||= OpenSSL::Digest.new('SHA256')
  end

  def payload_uuid
    @payload_uuid ||= Rails.cache.fetch('ios-udid', expires_in: 1.week) { SecureRandom.uuid.upcase }
  end

  def create_date
    Time.now.utc
  end

  def expire_date
    expire_time = 1 * 365 * 24 * 60 * 60  # 1 year
    create_date + expire_time
  end
end