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: access_token.rb
    path of file: ./repos/jwt_sessions/lib/jwt_sessions
    
    the code of the file until where you have to start completion: # frozen_string_literal: true

module JWTSessions
  class AccessToken
    attr_reader :payload, :uid, :expirat
    
    def initialize(csrf, payload, store, uid = SecureRandom.uuid, expiration = JWTSessions.access_expiration)
      @csrf       = csrf
      @uid        = uid
      @expiration = expiration
      @payload    = payload.merge("uid" => uid, "exp" => expiration.to_i)
      @store      = store
    end