code: public void add(
              ASN1ObjectIdentifier oid,
              String value) {
          ASN1EncodableVector v = new ASN1EncodableVector();
          v.add(oid);
          v.add(new DERPrintableString(value));
          add(new DERSet(new DERSequence(v)));
      }
docs: Appends the specified OID and value pair name component to the end of the
  current name.
  
  @param oid   the name component oid, e.g. {@link org.bouncycastle.asn1.x500.style.BCStyle#CN
  BCStyle.CN}
  @param value the value (e.g. "proxy")