1.写生成器，从文件中读取内容，再每一行读取的内容前加上 ‘***’之后返回给用户

def func(filename):
    word = input('输入你想找的内容：')
    with open(filename,mode='r',encoding='utf-8') as f:
        for line in f:
            if word in line:
                yield line

file = input('输入你要查找的文件:')
g = func(file)
for i in g:
    print('###'+ i.strip())