Python快速生成无用大文件（GB）

import time
def creatfilesize(n):
    local_time = time.strftime("%Y%m%d%H%M%S",time.localtime())
    file_name = r"D:\data\test\\" +str(local_time)+".txt"
    bigFile= open(file_name, 'w')
    bigFile.seek(1024*1024*1024*n) 
    bigFile.write('test')
    #bigFile.write("test")
    bigFile.close()
    print("ALL down !")

def main():
    n = 1 #生成1G大小的文件
    creatfilesize(n)