read files and write into another files python

1import sys
2import glob
3import os.path
4
5list_of_files = glob.glob('/Users/Emily/Topics/*.txt') #500 files
6
7for file_name in list_of_files:
8    print(file_name)
9
10    # This needs to be done *inside the loop*
11    f= open(file_name, 'r')
12    lst = []
13    for line in f:
14       line.strip()
15       line = line.replace("\n" ,'')
16       line = line.replace("//" , '')
17       lst.append(line)
18    f.close()
19
20    f=open(os.path.join('/Users/Emily/UpdatedTopics',
21    os.path.basename(file_name)) , 'w')
22
23    for line in lst:
24       f.write(line)
25    f.close()