'Create an NWFilter firewall driver
:param host: nova.virt.libvirt.host.Host instance
:param kwargs: currently unused'

def __init__(self, host, **kwargs):

    global libvirt
    if (libvirt is None):
        try:
            libvirt = importutils.import_module('libvirt')
        except ImportError:
            LOG.warning('Libvirt    module    could    not    be    loaded.    NWFilterFirewall    will    not    work    correctly.')
    self._host = host
    self.static_filters_configured = False
