getopt如何设置默认值

import getopt
import sys

def main(argv):
    input_file = ''
    output_file = ''
    default_value = 'default'

    try:
        opts, args = getopt.getopt(argv, "hi:o:", ["input=", "output="])
    except getopt.GetoptError:
        print('Usage: script.py -i <input_file> -o <output_file>')
        sys.exit(2)

    for opt, arg in opts:
        if opt == '-h':
            print('Usage: script.py -i <input_file> -o <output_file>')
            sys.exit()
        elif opt in ("-i", "--input"):
            input_file = arg
        elif opt in ("-o", "--output"):
            output_file = arg

    # 如果未提供输入文件，则使用默认值
    if not input_file:
        input_file = default_value

    # 如果未提供输出文件，则使用默认值
    if not output_file:
        output_file = default_value

    print('Input file:', input_file)
    print('Output file:', output_file)

if __name__ == "__main__":
    main(sys.argv[1:])