File parse in python

parse.py

f=open('/home/zhouji/temp/out5','r')
idx=0
ctn=set()
for line in f:
    ss=line.split("\001")
    s=ss[0]+ss[1]
    idx=idx+1
    if not s in ctn :
        print line.replace("\001","\\001").replace("\002","\\002").replace("\003","\\003")
        ctn.add(s)
print ctn