def media_file_set(type, link_type, value)
      media = media_file(type)

      # create a new isbn record if we need to
      if media.nil?
        media = ONIX::MediaFile.new
        media.media_file_type_code = type
        media.media_file_link_type_code = link_type
        product.media_files << media
      end

      # store the new value
      media.media_file_link = value.to_s
    end
def media_file_set(type, link_type, value)
      media = media_file(type)

      # create a new isbn record if we need to
      if media.nil?
        media = ONIX::MediaFile.new
        media.media_file_type_code = type
        media.media_file_link_type_code = link_type
        product.media_files << media
      end

      # store the new value
      media.media_file_link = value.to_s
    end
set the value of a particular ID