How can I Close DVD media?

Hello,
Does anyone know how can I close DVD media.
I’m using NeroApi to writing multisession DVD, but I can’t finalize this media. When I writing data on CD it was finalized succesfully then I don’t use NBF_CLOSE_SESSION flag in NeroBurn.
Anyone know how to finalize DVD?

Sorry
I have tested it with DVD+RW and I think that it is normal. Nero Burning ROM isn’t closing DVD+RW too. When I chec it with an DVD+R disc was closed succesfully