code: public GeneralSubtrees get(String name) throws IOException {
          if (name.equalsIgnoreCase(PERMITTED_SUBTREES)) {
              return (permitted);
          } else if (name.equalsIgnoreCase(EXCLUDED_SUBTREES)) {
              return (excluded);
          } else {
            throw new IOException("Attribute name not recognized by " +
                          "CertAttrSet:NameConstraintsExtension.");
          }
      }
docs: Get the attribute value.