code: @Override
      public boolean isGuest() {
          String userName = (String) getAttribute(IPerson.USERNAME);
          boolean isGuestUsername = PersonFactory.getGuestUsernames().contains(userName);
          boolean isAuthenticated = m_securityContext != null && m_securityContext.isAuthenticated();
          return isGuestUsername && !isAuthenticated;
      }
docs: Determines whether or not this person is a "guest" user.
  
  <p>This person is a "guest" if both of the following are true:
  
  <ol>
  <li>This person's user name is listed as a guest user account.
  <li>This person does not have a live instance ISecurityContext that states he/she has been
  successfully authenticated. (It can be either null or unauthenticated.)
  </ol>
  
  @return <code>true</code> If person is a guest, otherwise <code>false</code>