python zip和tar两种格式的压缩与解压

def unzip(zip_package, directory):    print "unzip the package ", zip_package, " to ", directory    if zipfile.is_zipfile(zip_package):        unzip_cmd = "python -m zipfile  -e " + zip_package + " " + directory        os.system(unzip_cmd)    else:        print "ERROR: unzip failed, please check the zip package again..."    def zip(zipfilename, directory):    print "zip directory ", directory, " to the ", zipfilename    zip_cmd = "python -m zipfile -c " + zipfilename + " " + directory    print zip_cmd    os.system(zip_cmd)    def tar(tarfilename, directory):    print "tar the package ", tarfilename        with tarfile.open(tarfilename, "w:") as tarObj:        tarObj.add(directory, arcname=os.path.basename(directory))        def untar(tar_package, directory):    print "untar the package ", tar_package, " to ", directory    tarHandle = tarfile.open(tar_package, "r:")    #for filename in tarHandle.getnames():        #print filename    tarHandle.extractall(directory)    tarHandle.close()