protected function addParameter($name, $location, $required, $description = null)
    {
        $name = trim($name);

        if (strpos($name, ',') !== false) {
            foreach (explode(',', $name) as $subname) {
                $this->addParameter($subname, $location, $required, $description);
            }

            return;
        }

        $this->parameters[$name] = Parameter::build($location, $required, $description);
    }