'Wrapper method for renewing DHCP lease via given client
Supporting:
* udhcpc
* dhclient'

def renew_lease(self, fixed_ip=None, dhcp_client='udhcpc'):

    supported_clients = ['udhcpc', 'dhclient']
    if (dhcp_client not in supported_clients):
        raise tempest.lib.exceptions.InvalidConfiguration(('%s    DHCP    client    unsupported' % dhcp_client))
    if ((dhcp_client == 'udhcpc') and (not fixed_ip)):
        raise ValueError("need    to    set    'fixed_ip'    for    udhcpc    client")
    return getattr(self, ('_renew_lease_' + dhcp_client))(fixed_ip=fixed_ip)
