parser.add_argument('-s','--feature-selection-style',default='independent',choices={'independent','shared'},help="The feature selection style (only for multivariate classification with the LUT trainer).")
parser.add_argument('-D','--database-directory',default='Database',help="The directory where to download the database to (or read it from if it already exists)")
parser.add_argument('-d','--digits',type=int,nargs="+",choices=range(10),default=[5,6],help="Select the digits you want to compare.")
parser.add_argument('-a','--all-digits',action='store_true',help="Use all digits")
parser.add_argument('-n','--number-of-elements',type=int,help="For testing purposes: limit the number of training and test examples for each class.")