python's search function

def fetch(a):
    print('这是所要查询的内容')
    backend_data = 'backend %s'% a
    with open('haproxy.conf','r') as f:
        Itag=False
        res=[]
        for i in f:
            if backend_data==i.strip():
                Itag=True
                continue
            if Itag and i.startswith('backend'):
                break
            if Itag:
                print(i,end='')
                res.append(i)
    return res

def add():
    pass
def delete():
    pass
def change():
    pass
if __name__=='__main__':
    msg='''
        1: Query
        2: Increase 
        3: Delete 
        4: Review 
        5: Release 

    '' ' 
    msg_txt = { 
        '. 1 ': FETCH, 
        ' 2 ': the Add, 
        ' 3 ': Delete, 
        ' 4 ': Change, 
        ' 5 ': Exit 
    } 
    the while True : 
        Print (msg) 
        RES = the iNPUT ( 'Please input options:') Strip (). 
        IF not RES: 
            the Continue 
        IF RES == 5: 
            BREAK 
        the data = the iNPUT ( 'user enter data to be queried:') 
        RET = msg_txt [RES] (Data) 
        Print (RET)