docs: function importAuthCodes(channel, codes, settings) {
      var authDir, outFile, outFileBak;
  
      channel.registry.importClients(codes);
  
      authDir = settings.authDir;
      if (settings.dumpCodes !== false) {
          outFile = settings.outFile || 'codes.imported.csv';
          if (!path.isAbsolute(outFile)) {
              outFile = path.join(settings.authDir, outFile);
          }
          outFileBak = outFile + '.bak';
  
          fs.rename(outFile, outFileBak, function() {
              var NDDB, db;
              NDDB = require('NDDB').NDDB;
              db = new NDDB();
              db.importDB(codes);
              // Async function. Throws errors.
              db.save(outFile);
          });
      }
  
      // Not needed anymore.
      delete settings.authDir;
  }