docs: public static SingleSignonToken getSSOToken(Subject subject) {
          SingleSignonToken ssoToken = null;
          Set<SingleSignonToken> ssoTokens = subject.getPrivateCredentials(SingleSignonToken.class);
          Iterator<SingleSignonToken> ssoTokensIterator = ssoTokens.iterator();
          if (ssoTokensIterator.hasNext()) {
              ssoToken = ssoTokensIterator.next();
          }
          return ssoToken;
      }