python 对文件做类别标签

import sys
sys.path.append('path')
lst = open('Eniminate.txt','rb')
line = lst.readlines()
lislen=len(line)
fl = open('fgood.txt','wb')
ml=open('mgood.txt','wb')
for li in line:
if 'M' in li:
ml.write(li)
else:
fl.write(li)
lst.close()
ml.close()
fl.close()