How i can get the amount from the rates API?

[silambarasanmuthuvel]

shipment_builder.add_description 'White coffee mug' shipment_builder.add_payment_information 'ACCOUNT_NUMBER' shipment_builder.add_service '65' # returned in rates response

how I can parse the get the amount from the rates API to add the amount to the shipment_builder.add_service '65'