def set_vif_host_backend_bridge_config(conf, brname, tapname=None):
 conf.net_type = 'bridge'
 conf.source_dev = brname
 if tapname:
  conf.target_dev = tapname

def set_vif_host_backend_bridge_config ( conf , brname , tapname = None ) : conf . net_type = 'bridge' conf . source_dev = brname if tapname : conf . target_dev = tapname
populate a libvirtconfigguestinterface instance with host backend details for a software bridge .