docs: def random_ipv4(cidr='10.0.0.0/8'):
      """
      Return a random IPv4 address from the given CIDR block.
  
      :key str cidr: CIDR block
      :returns: An IPv4 address from the given CIDR block
      :rtype: ipaddress.IPv4Address
      """
      try:
          u_cidr = unicode(cidr)
      except NameError:
          u_cidr = cidr
      network = ipaddress.ip_network(u_cidr)
      start = int(network.network_address) + 1
      end = int(network.broadcast_address)
      randint = random.randrange(start, end)
      return ipaddress.ip_address(randint)