Python 2 to 3 Conversion

[Wildman]

I have a bit of code I found on the web that will return
the ip address of the named network interface.  The code
is for Python 2 and it runs fine.  But, I want to use the
code with Python 3.  Below is the code followed by the error
message.  Suggestions appreciated.

#!/usr/bin/env python3

import socket
import fcntl
import struct

def get_ip_address(ifname):
    s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
    return socket.inet_ntoa(fcntl.ioctl(
        s.fileno(),
        0x8915,  # SIOCGIFADDR
        struct.pack('256s', ifname[:15])
        )[20:24])
print(get_ip_address("eth0"))
print(get_ip_address("lo"))


Traceback (most recent call last):
  File "./test.py", line 14, in <module>
    print(get_ip_address("eth0"))
  File "./test.py", line 12, in get_ip_address
    struct.pack('256s', ifname[:15])
struct.error: argument for 's' must be a bytes object

-- 
<Wildman> GNU/Linux user #557453
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