'Fill out some options in msg'

def fill(self, wanted_opts, msg):

    if (msg.SUBNET_MASK_OPT in wanted_opts):
        msg.add_option(pkt.DHCP.DHCPSubnetMaskOption(self.subnet))
    if ((msg.ROUTERS_OPT in wanted_opts) and (self.router_addr is not None)):
        msg.add_option(pkt.DHCP.DHCPRoutersOption(self.router_addr))
    if ((msg.DNS_SERVER_OPT in wanted_opts) and (self.dns_addr is not None)):
        msg.add_option(pkt.DHCP.DHCPDNSServersOption(self.dns_addr))
    msg.add_option(pkt.DHCP.DHCPIPAddressLeaseTimeOption(self.lease_time))
