验证命令行参数的简单方法

import argparse

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

    args = parser.parse_args()
    result = args.accumulate(args.integers)
    print(result)

if __name__ == '__main__':
    main()

error: argument integers: expected at least one argument