code: protected int getUserIdSendError(String username, MessageContext ctx) {
      try {
        return getUser(username).getId();
      } catch (IllegalStateException ex) {
        silent.send(getLocalizedMessage(USER_NOT_FOUND, ctx.user().getLanguageCode(), username), ctx.chatId());
        throw propagate(ex);
      }
    }
docs: Gets the user with the specified username. If user was not found, the bot will send a message on Telegram.
  
  @param username the username of the required user
  @param ctx      the message context with the originating user
  @return the id of the user