protected function callbackAllowsGuests($callback)
    {
        $parameters = (new ReflectionFunction($callback))->getParameters();

        return isset($parameters[0]) && $this->parameterAllowsGuests($parameters[0]);
    }
protected function callbackAllowsGuests($callback)
    {
        $parameters = (new ReflectionFunction($callback))->getParameters();

        return isset($parameters[0]) && $this->parameterAllowsGuests($parameters[0]);
    }
protected function callbackAllowsGuests ( $ callback ) { $ parameters = ( new ReflectionFunction ( $ callback ) ) -> getParameters ( ) ; return isset ( $ parameters [ 0 ] ) && $ this -> parameterAllowsGuests ( $ parameters [ 0 ] ) ; }
Determine if the callback allows guests.

@param  callable  $callback
@return bool
Determine if the callback allows guests .