public function setPathSeparator(string $separator)
    {
        if ($this instanceof ParentNodeDefinitionInterface) {
            if (method_exists($this, 'getChildNodeDefinitions')) {
                foreach ($this->getChildNodeDefinitions() as $child) {
                    $child->setPathSeparator($separator);
                }
            } else {
                @trigger_error('Passing a ParentNodeDefinitionInterface without getChildNodeDefinitions() is deprecated since Symfony 4.1.', E_USER_DEPRECATED);
            }
        }

        $this->pathSeparator = $separator;

        return $this;
    }