Need help with flycheck and etc-sudoers-mode

[lester]

I want to install `flycheck` together with 
https://github.com/emacsmirror/etc-sudoers-mode.

When I run gnu emacs, I get:

    Error (use-package): etc-sudoers-mode/:catch: Symbol’s value as 
variable is void: sudoers Disable showing Disable logging

Have you any ideas what could be wrong? Thanks

My `.emacs.d/init.el`:

    ;; use straight.el for package management
    (defvar bootstrap-version)
    (let ((bootstrap-file
           (expand-file-name "straight/repos/straight.el/bootstrap.el" 
user-emacs-directory))
          (bootstrap-version 6))
      (unless (file-exists-p bootstrap-file)
        (with-current-buffer
            (url-retrieve-synchronously

"https://raw.githubusercontent.com/radian-software/straight.el/develop/install.el";
             'silent 'inhibit-cookies)
          (goto-char (point-max))
          (eval-print-last-sexp)))
      (load bootstrap-file nil 'nomessage))

    ;; install use-package using straight.el
    (straight-use-package 'use-package)

    ;; configure use-package to use straight.el by default
    (use-package straight
      :custom
      (straight-use-package-by-default t))

    ;; disable startup screen
    (setq inhibit-startup-screen t)

    ;; disable menu bar, scroll bar, and tool bar
    (menu-bar-mode -1)
    (toggle-scroll-bar -1)
    (tool-bar-mode -1)

    ;; disable dialog boxes
    (setq use-dialog-box nil)

    ;; set custom color scheme
    (use-package doom-themes)
    (use-package doom-moonfly-theme
      :straight (:host github :repo "stackmystack/doom-moonfly-theme"
                   :branch "master"))
    (load-theme 'doom-moonfly t)

    ;; set default font
    (set-face-attribute 'default nil
                    :family "MesloLGS Nerd Font Mono"
                    :height 130
                    :weight 'normal
                    :width 'normal)

    ;; always ask using y or n instead yes or no
    (defalias 'yes-or-no-p 'y-or-n-p)

    ;; disable annoying bell
    (setq ring-bell-function 'ignore)

    ;; auto close bracket insertion
    (electric-pair-mode 1)

    ;; display line numbers
    (require 'display-line-numbers)

    (defcustom display-line-numbers-exempt-modes
      '(vterm-mode eshell-mode shell-mode term-mode ansi-term-mode)
      "Major modes on which to disable line numbers."
      :group 'display-line-numbers
      :type 'list
      :version "green")

    (defun display-line-numbers--turn-on ()
      "Turn on line numbers except for certain major modes.
    Exempt major modes are defined in `display-line-numbers-exempt-modes'."
      (unless (or (minibufferp)
                  (member major-mode display-line-numbers-exempt-modes))
        (display-line-numbers-mode)))

    (global-display-line-numbers-mode)

    ;; C-x C-; is not properly handled in terminal emulator so let's
    ;; add custom key binding for toggling comments in line
    (defun toggle-comment-on-line ()
      "comment or uncomment current line"
      (interactive)
      (comment-or-uncomment-region (line-beginning-position) 
(line-end-position)))
    (global-set-key (kbd "C-c ;") #'toggle-comment-on-line)

    ;; change indentation level for languages with C-like syntax
    (setq-default c-basic-offset 4)

    ;; auto completion
    (use-package company)
    (add-hook 'after-init-hook 'global-company-mode)
    (setq company-minimum-prefix-length 1
          company-idle-delay 0.0) ;; default is 0.2

    ;; lsp mode
    ;(use-package lsp-mode)

    ;; flycheck
    (use-package flycheck)
    (add-hook 'after-init-hook #'global-flycheck-mode)

    ;; sudoers mode
    (use-package etc-sudoers-mode)

    ;; systemd mode
    (use-package systemd)