func IsExtInCert(cert *x509.Certificate, oid asn1.ObjectIdentifier) bool {
	if cert != nil && GetExtFromCert(cert, oid) != nil {
		return true
	}
	return false
}
func IsExtInCert(cert *x509.Certificate, oid asn1.ObjectIdentifier) bool {
	if cert != nil && GetExtFromCert(cert, oid) != nil {
		return true
	}
	return false
}
// IsExtInCert is equivalent to GetExtFromCert() != nil.