How to use the @node-red/util/lib/log._ function in @node-red/util

fs.copy(backupPath,path,function(backupCopyErr) {
                            if (backupCopyErr) {
                                // Restore backup failed
                                log.warn(log._("storage.localfilesystem.restore-fail",{message:backupCopyErr.toString(),type:type}));
                                resolve([]);
                            } else {
                                // Loop back in to load the restored backup
                                resolve(readFile(path,backupPath,emptyResponse,type));
                            }
                        });
                        return;

fs.readFile(path,'utf8',function(err,data) {
            if (!err) {
                if (data.length === 0) {
                    log.warn(log._("storage.localfilesystem.empty",{type:type}));
                    try {
                        var backupStat = fs.statSync(backupPath);
                        if (backupStat.size === 0) {
                            // Empty flows, empty backup - return empty flow
                            return resolve(emptyResponse);
                        }
                        // Empty flows, restore backup
                        log.warn(log._("storage.localfilesystem.restore",{path:backupPath,type:type}));
                        fs.copy(backupPath,path,function(backupCopyErr) {
                            if (backupCopyErr) {
                                // Restore backup failed
                                log.warn(log._("storage.localfilesystem.restore-fail",{message:backupCopyErr.toString(),type:type}));
                                resolve([]);
                            } else {
                                // Loop back in to load the restored backup
                                resolve(readFile(path,backupPath,emptyResponse,type));

resolve([]);
                            } else {
                                // Loop back in to load the restored backup
                                resolve(readFile(path,backupPath,emptyResponse,type));
                            }
                        });
                        return;
                    } catch(backupStatErr) {
                        // Empty flow file, no back-up file
                        return resolve(emptyResponse);
                    }
                }
                try {
                    return resolve(parseJSON(data));
                } catch(parseErr) {
                    log.warn(log._("storage.localfilesystem.invalid",{type:type}));
                    return resolve(emptyResponse);
                }
            } else {
                if (type === 'flow') {
                    log.info(log._("storage.localfilesystem.create",{type:type}));
                }
                resolve(emptyResponse);
            }
        });
    });

});
                        return;
                    } catch(backupStatErr) {
                        // Empty flow file, no back-up file
                        return resolve(emptyResponse);
                    }
                }
                try {
                    return resolve(parseJSON(data));
                } catch(parseErr) {
                    log.warn(log._("storage.localfilesystem.invalid",{type:type}));
                    return resolve(emptyResponse);
                }
            } else {
                if (type === 'flow') {
                    log.info(log._("storage.localfilesystem.create",{type:type}));
                }
                resolve(emptyResponse);
            }
        });
    });

fs.readFile(path,'utf8',function(err,data) {
            if (!err) {
                if (data.length === 0) {
                    log.warn(log._("storage.localfilesystem.empty",{type:type}));
                    try {
                        var backupStat = fs.statSync(backupPath);
                        if (backupStat.size === 0) {
                            // Empty flows, empty backup - return empty flow
                            return resolve(emptyResponse);
                        }
                        // Empty flows, restore backup
                        log.warn(log._("storage.localfilesystem.restore",{path:backupPath,type:type}));
                        fs.copy(backupPath,path,function(backupCopyErr) {
                            if (backupCopyErr) {
                                // Restore backup failed
                                log.warn(log._("storage.localfilesystem.restore-fail",{message:backupCopyErr.toString(),type:type}));
                                resolve([]);
                            } else {
                                // Loop back in to load the restored backup
                                resolve(readFile(path,backupPath,emptyResponse,type));
                            }
                        });
                        return;
                    } catch(backupStatErr) {
                        // Empty flow file, no back-up file
                        return resolve(emptyResponse);
                    }
                }

fs.fsync(fd,function(err) {
                        if (err) {
                            log.warn(log._("storage.localfilesystem.fsync-fail",{path: path, message: err.toString()}));
                        }
                        stream.end(resolve);
                    });
                });