def price_set(type, num)
      p = price_get(type)

      # create a new isbn record if we need to
      if p.nil?
        supply = find_or_create_supply_detail
        p = ONIX::Price.new
        p.price_type_code = type
        supply.prices << p
      end

      # store the new value
      p.price_amount = num
    end
def price_set(type, num)
      p = price_get(type)

      # create a new isbn record if we need to
      if p.nil?
        supply = find_or_create_supply_detail
        p = ONIX::Price.new
        p.price_type_code = type
        supply.prices << p
      end

      # store the new value
      p.price_amount = num
    end
set the value of a particular price