Generate packing slip with different format for last order

generate_packing_slip.rake

namespace :gps do
  task ga4: :environment do
    pdf = Couriers::Base::A4PackingSlipPublisher.new(Order.last)
    pdf.render_file '/Users/ZZ/Desktop/a.pdf'
  end

  task ga6: :environment do
    pdf = Couriers::Base::A6PackingSlipPublisher.new(Order.last)
    pdf.render_file '/Users/ZZ/Desktop/a.pdf'
  end

end