code: public static function register($prepend = true, $callback = null, $app = null)
      {
          if (!static::$registered) {
              static::$registered = spl_autoload_register(array('\\Sbp\\Laravel\\ClassLoader', 'load'), true, $prepend);
              if (is_null($app)) {
                  $app = __DIR__.'/../../../../../../app';
              }
              if (!file_exists($app.'/storage') || !is_writable($app.'/storage')) {
                  throw new SbpException("Laravel app and/or writable storage directory not found at $app, please specify the path with the following code:\nSbp\\Laravel\\ClassLoader::register(true, 'sha1', \$laravelAppPath)");
              }
              Sbp::writeIn(Sbp::SAME_DIR);
              Sbp::fileExists($app.'/routes');
              $storage = $app.'/storage/sbp';
              if (!file_exists($storage)) {
                  if (mkdir($storage, 0777)) {
                      file_put_contents($storage.'/.gitignore', "*\n!.gitignore");
                  }
              }
              Sbp::writeIn($storage, $callback);
          }
      }
docs: Register the given class loader on the auto-loader stack.
  
  @return void