private function getXAndY(Object $children, &$x, &$y)
{
Assertion::isInstanceOf($children, ExplicitlyTaggedObject::class, 'Unable to load the key');
Assertion::isArray($children->getContent(), 'Unable to load the key');
Assertion::isInstanceOf($children->getContent()[0], BitString::class, 'Unable to load the key');
$bits = $children->getContent()[0]->getContent();
$bits_length = mb_strlen($bits, '8bit');
Assertion::eq('04', mb_substr($bits, 0, 2, '8bit'), 'Unsupported key type');
$x = mb_substr($bits, 2, ($bits_length - 2) / 2, '8bit');
$y = mb_substr($bits, ($bits_length - 2) / 2 + 2, ($bits_length - 2) / 2, '8bit');
}