import argparse
parser = argparse.ArgumentParser(description='Process some integers.')
# Positional arguments
parser.add_argument('integers', metavar='N', type=int, nargs='+',
help='an integer for the accumulator')
# Optional arguments
parser.add_argument('--sum', dest='accumulate', action='store_const',
const=sum, default=max,
help='sum the integers (default: find the max)')