How to use the loopback4-authentication.AuthErrorKeys.UnknownError function in loopback4-authentication

throw new HttpErrors.Unauthorized(AuthErrorKeys.ClientInvalid);
    }
    try {
      const codePayload: ClientAuthCode = {
        clientId,
        user: this.user,
      };
      const token = jwt.sign(codePayload, client.secret, {
        expiresIn: client.authCodeExpiration,
        audience: clientId,
        subject: this.user.username,
        issuer: process.env.JWT_ISSUER,
      });
      response.redirect(`${client.redirectUrl}?code=${token}`);
    } catch (error) {
      throw new HttpErrors.InternalServerError(AuthErrorKeys.UnknownError);
    }
  }