python文件查询修改

f = open('cc','r',encoding='utf-8')
f_new = open('cc.bak','w',encoding='utf8')
for line in f:
    if ' 想让我知难而退' in line:
        line = line.replace('想让我知难而退','想让我主动出击')
    f_new.write(line)
f.close()
f_new.close()


with open('cc','r',encoding='utf-8') as f ,\
    open('cc2','r',encoding='utf-8') as f2:  #同时打开多个文件