stripe-ruby/lib/stripe/api_operations/update.rb

module Stripe
  module APIOperations
    module Update
      def save
        if @unsaved_values.length > 0
          values = @unsaved_values.reduce({}) do |h, k| 
            h.update(k => @values[k].nil? ? '' : @values[k])
          end
          values.delete(:id)
          response, api_key = Stripe.request(:post, url, @api_key, values)
          refresh_from(response, api_key)
        end
        self
      end
    end
  end
end