code: public GenericUser getUserForUserReference(String userReference) {
      	GenericUser user = getReference(GenericUser.class, userReference);
          if (user == null) {
              fail("No user of type '" + userReference + "' is found. Available user references are: " + getObjectReferenceMap(GenericUser.class).keySet().toString());
          }
          return user;
      }
docs: Find a {@link GenericUser} by its reference name
  
  @param userType
  @return {@link GenericUser}