code: public void delete(String name) throws IOException {
          if (name.equalsIgnoreCase(SKIP_CERTS))
              throw new IOException("Attribute " + SKIP_CERTS +
                                    " may not be deleted.");
          else
              throw new IOException("Attribute name not recognized by " +
                                    "CertAttrSet:InhibitAnyPolicy.");
      }
docs: Delete the attribute value.
  
  @param name name of attribute to delete. Must be SKIP_CERTS.
  @throws IOException on error.  In this case, IOException will always be
  thrown, because the only attribute, SKIP_CERTS, is
  required.