protected function _formatErrors(array $libxmlErrors=array())
	{
		return 'XSD validation failed with following messages:' . PHP_EOL . implode('', array_map(
			function (\libXMLError $xmlError) {
				return sprintf(
					'[%s:%d] %s',
					$xmlError->file,
					$xmlError->line,
					$xmlError->message
				);
			},
			$libxmlErrors
		));
	}