<s> from oslo_config import cfg <EOL> from stevedore import driver <EOL> ipv6_backend_opt = cfg . StrOpt ( '<STR_LIT>' , <EOL> default = '<STR_LIT>' , <EOL> help = '<STR_LIT>' ) <EOL> CONF = cfg . CONF <EOL> CONF . register_opt ( ipv6_backend_opt ) <EOL> IMPL = None <EOL> def reset_backend ( ) : <EOL> global IMPL <EOL> IMPL = driver . DriverManager ( "<STR_LIT>" , <EOL> CONF . ipv6_backend ) . driver <EOL> def to_global ( prefix , mac , project_id ) : <EOL> return IMPL . to_global ( prefix , mac , project_id ) <EOL> def to_mac ( ipv6_address ) : <EOL> return IMPL . to_mac ( ipv6_address ) <EOL> reset_backend ( ) </s>
