code: @Nonnull
    public ELoginResult loginUser (@Nullable final String sLoginName, @Nullable final String sPlainTextPassword)
    {
      return loginUser (sLoginName, sPlainTextPassword, (Iterable <String>) null);
    }
docs: Login the passed user without much ado.
  
  @param sLoginName
  Login name of the user to log-in. May be <code>null</code>.
  @param sPlainTextPassword
  Plain text password to use. May be <code>null</code>.
  @return Never <code>null</code> login status.