public static function filterConfig(array $config, $target = 'PHP')
	{
		$filteredConfig = [];
		foreach ($config as $name => $value)
		{
			if ($value instanceof FilterableConfigValue)
			{
				$value = $value->filterConfig($target);
				if (!isset($value))
				{
					continue;
				}
			}
			if (is_array($value))
			{
				$value = self::filterConfig($value, $target);
			}
			$filteredConfig[$name] = $value;
		}

		return $filteredConfig;
	}