python Save the output of a shell command into a text file

I want to save the output of a shell command into a textfile via python. This is my actual, pretty basic python code:

Edit here is the final script, thank you for your help :)

import subprocess

ip_adress_4 = 0    
pr = open("pointer_record.txt", "w")

while (ip_adress_4 < 255):
    ip_adress_4 = ip_adress_4 + 1
    ip_adress = '82.198.205.%d' % (ip_adress_4,)
    subprocess.Popen("host %s" % ip_adress, stdout=pr, shell=True)