Fixed main.py

[EuiseongHong]

Modifications Made:
line 5:
li = open(path, 'w') --> lines = open(path, 'r').read().split('\n')
This change was made to ensure that the file is opened with read option and each line was added in as a element in each list.
The previous code did not return anything because we did not initialize any value in lines. Also it opened the file with w option even though we needed to read the lines off the file with the r option
line 14:
file = file.replace('\', '\') --> file = file.replace('\', '\\')
This change was made so that \ will be replaced with \\ not \ itself like the previous code.
The previous code was wrong because it was replacing // with // which does not make any difference.
line 37-39:
with open(path, 'r') as f:
for file in file_list:
f.write('\n')

-->

with open(path, 'w') as f:
for file in file_list:
f.write(file + '\n')
This change was made so that we open the file with w option and also write the strings with \n.
The previous code opened the file with r option, which cannot write in the file. Also it did not write the strings as intended.

These are the modifications I made. Thank you!!