#import random
#from netaddr.ip import IPNetwork, IPAddress
#import string 
#random.seed()
#ip_a = IPAddress('2001::cafe:0') + random.getrandbits(16)
#ip_n = IPNetwork(ip_a)
#ip_n.prefixlen = 64

#print (ip_a)
#print (ip_n)

"""
Generate a random IPv6 address for a specified subnet
"""

from random import seed, getrandbits
from ipaddress import IPv6Network, IPv6Address

subnet = 'fd00::/8'

seed()
network = IPv6Network(subnet)
address = IPv6Address(network.network_address + getrandbits(network.max_prefixlen - network.prefixlen))

print(address)