Call repository function in static funcion.

[andrei0807]

I need user list in static function of controller.

export class NotificationController {
  constructor(
    @repository(UserRepository) public userRepository: UserRepository,
  ) {
  }

  public static async sendPushNotification(userId: string) {
    const userInfo = await this.userRepository.findById(userId, {fields: ['pushToken']});
    // send push code
  }
}

But I can not use this and call repository function.
Is there solution for this?