docs: function runExtensions(settings) {
    var extensions = settings.extensions,
        channels = settings.channels,
        connection = settings.connection,
        userPackage = settings.userPackage,
        server = settings.server;
  
    // For every extension the user listed...
  
    extensions.forEach(function (extension) {
  
      // Find the callbacks associated with that extension.
      var callbacks = channels[extension];
  
      // If there aren't any, we're trying to extend something that hasn't
      // been defined yet.
      if (!callbacks) {
        throw new Error('Can not extend channel ' + extension + ' because it does not exist.');
  
        // Otherwise, we can call each one.
      } else {
        callbacks.forEach(function (callback) {
          return callback(connection, userPackage, server);
        });
      }
    });
  }