    # File lib/active_merchant/billing/integrations/hi_trust/helper.rb, line 32
              def amount=(money)
                cents = money.respond_to?(:cents) ? money.cents : money

                if money.is_a?(String) or cents.to_i < 0
                  raise ArgumentError, 'money amount must be either a Money object or a positive integer in cents.'
                end

                add_field(mappings[:amount], cents)
              end