selection.add_option('--min-filesize',metavar='SIZE',dest='min_filesize',help="Do not download any videos smaller than SIZE (e.g. 50k or 44.6m)",default=None)
selection.add_option('--max-filesize',metavar='SIZE',dest='max_filesize',help="Do not download any videos larger than SIZE (e.g. 50k or 44.6m)",default=None)
selection.add_option('--date',metavar='DATE',dest='date',help='download only videos uploaded in this date',default=None)