[Python-Dev] raising a io exception when fileno is requested on a tarfile FileInFile

Hi, When you call extractfile() on a TarFile, the result is a buffered version of a _FileInFile pseudo-file. When fileno() is called on this resulting file, fileno() it not exist (understandably) and an AttributeError is raised. I would like to suggest raising an io.UnsupportedOperation instead, so that file would act more like other file-like objects.