parser.add_argument('mission',help='mission for files to be downloaded. Use "all" to download everything, "legacybase" to download base data for ISIS<4.1.0.')
parser.add_argument('dest',help='the destination to download files from source')
parser.add_argument('--dry-run',help="run a dry run for rclone value should be a boolean",default=False,action='store_true')