使用Python瞬间生成超大文件

import timedef creatfilesize(n):    local_time = time.strftime("%Y%m%d%H%M%S",time.localtime())    file_name = "E:\\"+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 !"if __name__ == '__main__':    n = input("input:")    creatfilesize(n)