code: public static long findUniqueUserCount(EntityManager em) {
          TypedQuery<Long> query = em.createNamedQuery("PrincipalUser.findUniqueUserCount", Long.class);
  
          return query.getSingleResult();
      }
docs: Returns the unique user count.
  
  @param   em  The entity manager to use.
  
  @return  The unique user count.