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: jwt.rb
    path of file: ./repos/gitlabhq/lib/gitlab/ci
    
    the code of the file until where you have to start completion: # frozen_string_literal: true

module Gitlab
  module Ci
    class Jwt
      NOT_BEFORE_TIME = 5
     
    
      def key
        @key ||= begin
          key_data = Gitlab::CurrentSettings.ci_jwt_signing_key

          raise NoSigningKeyError unless key_data

          OpenSSL::PKey::RSA.new(key_data)
        end