Fix all files in a folder with python

fix.py

import os

folder = 'D:\Projects\python\poems_need_fixing\\'

for filename in os.listdir(folder):
    full_filename = folder+filename
    print " START " + filename
    r = open(full_filename,'r')
    lines = r.readlines()
    open(full_filename, "w").close()
    newLines = [line.replace('```','\r```') for line in lines]
    f = open(full_filename,'r+')
    f.truncate(0)
    f.writelines(newLines)
    f.close()
    print " FINISHED " + filename