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