Because even if it doesn't make a difference in practice, it is
technically more correct to call static methods statically. It
also better advertise that those methods can be used from any context.
When the xml file is not a standard xml file, the `simplexml_load_string` will return false, this will cause an error on "$xml->getNamespaces(true);" . So instead of showing the error, we throw an exception.
GreatHumorist