protected static function _assets($type = null) {
		$assets = static::$_assets + [
			'js' => ['suffix' => '.js', 'filter' => null, 'paths' => [
				'{:base}/{:library}/js/{:path}' => ['base', 'library', 'path'],
				'{:base}/js/{:path}' => ['base', 'path']
			]],
			'css' => ['suffix' => '.css', 'filter' => null, 'paths' => [
				'{:base}/{:library}/css/{:path}' => ['base', 'library', 'path'],
				'{:base}/css/{:path}' => ['base', 'path']
			]],
			'image' => ['suffix' => null, 'filter' => null, 'paths' => [
				'{:base}/{:library}/img/{:path}' => ['base', 'library', 'path'],
				'{:base}/img/{:path}' => ['base', 'path']
			]],
			'generic' => ['suffix' => null, 'filter' => null, 'paths' => [
				'{:base}/{:library}/{:path}' => ['base', 'library', 'path'],
				'{:base}/{:path}' => ['base', 'path']
			]]
		];
		if ($type) {
			return isset($assets[$type]) ? $assets[$type] : null;
		}
		return $assets;
	}