code: public function processArguments(array $arguments) : array
      {
          foreach ($arguments as $key => $value) {
              if (is_string($value) && 0 === strpos($value, '@')) {
                  $name = substr($value, 1);
  
                  if (isset($this->contextCallbacks[$name])) {
                      $arguments[$key] = call_user_func($this->contextCallbacks[$name]);
                  }
              }
          }
  
          return $arguments;
      }
docs: @param array $arguments
  
  @return array