Hash function in python

[hamedpersian]

I have written some hash code and it supposed to have a 32 bits output. But i don't know how to make it 32 bit as the output. please help me with this. Here is my code:

import BitVector
import io
import math
import struct

if __name__ == "__main__":
    message = raw_input("your message:")
    f= open('file.dat','w')
    f.write(message)
    f.close()

    f = open('file.dat')
    while 1:
       r = f.readline(1)
       hx = r.encode("hex")
       data = bin(int(hx, 16))[2:]
       key = 11111111
       x = int(data) ^ int(key)
       print hex(x)
       if not r:break
    f.close()