how do i split a joining multiple file

[DYPH]

i've a problem to split a join multiple file.
here's my code to join a multiple file.

import sys
import os
 
f = open("e:/Dev/1.jpg", "rb")
g = open("e:/Dev/2.mp3", "rb")
dataList = []
dataList.append(f.read())
dataList.append(g.read())
g.close()
 
data = f.read()
new = f.name
f = open(new, 'wb')
for data in dataList:
    f.write(data)
f.close()
os.remove(g.name)

my goal is to hide 2nd file in 1st file. a 1st file can be accessed although it contains 2nd file in it.

but now a problem is to split this kind of file, so it'll back to original form.
note that a join and split code must be separated.
any idea would be help.