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: delivery.rb
    path of file: ./repos/rpush/lib/rpush/daemon/gcm
    
    the code of the file until where you have to start completion: module Rpush
  module Daemon
    module Gcm
      # https://firebase.google.com/docs/cloud-messaging/server
      class Delivery < Rpush::Daemon::Delivery
        include MultiJsonHelper

        host = 
    
        def handle_response(response)
          case response.code.to_i
          when 200
            ok(response)
          when 400
            bad_request
          when 401
            unauthorized
          when 500
            internal_server_error(response)
          when 502
            bad_gateway(response)
          when 503
            service_unavailable(response)
          when 500..599
            other_5xx_error(response)
          else
            fail Rpush::DeliveryError.new(response.code.to_i, @notification.id, Rpush::Daemon::HTTP_STATUS_CODES[response.code.to_i])
          end