protected function getAttributesConfig(array $siteConfig)
	{
		$attrNames = $this->getAttributeNamesFromRegexps($siteConfig['extract']);
		foreach ($siteConfig['scrape'] as $scrapeConfig)
		{
			$attrNames += $this->getAttributeNamesFromRegexps($scrapeConfig['extract']);
		}

		$attributes = $siteConfig['attributes'] + array_fill_keys(array_keys($attrNames), []);
		foreach ($attributes as &$attrConfig)
		{
			$attrConfig += ['required' => false];
		}
		unset($attrConfig);

		return $attributes;
	}