Karaoke cleaner

#!/usr/bin/python

import os
import os.path
import sys

def process_zip(path):
    os.system("unzip %s" % path)

def process_cdg(path):
    pass

def process_mp3(path):
    print("found mp3", path)

def main():
    if (len(sys.argv) < 2):
        usage()
        exit()

    for (path, _, files) in os.walk(sys.argv[1]):
        for name in files:
            filepath = os.path.join(path, name)
            ext = os.path.splitext(filepath)[1]

            try:
                {'.cdg':    process_cdg,
                 '.zip':    process_zip,
                 '.mp3':    process_mp3}[ext](filepath)
            except KeyError:
                pass

def usage():
    print("Usage: crawler path")

main()