code: @SuppressWarnings("unchecked") // Checked with instanceof
      public void set(String name, Object obj) throws IOException {
          if (name.equalsIgnoreCase(USAGES)) {
              if (!(obj instanceof Vector)) {
                  throw new IOException("Attribute value should be of type Vector.");
              }
              this.keyUsages = (Vector<ObjectIdentifier>)obj;
          } else {
            throw new IOException("Attribute name [" + name +
                                  "] not recognized by " +
                                  "CertAttrSet:ExtendedKeyUsageExtension.");
          }
          encodeThis();
      }
docs: Set the attribute value.