   ;; Enable company completion on TAB when in shell mode.
   ;; (company-mode)
   ;; (bind-key "TAB" #'company-manual-begin shell-mode-map)
-  (setq company-backends '(company-files
+  (validate-setq company-backends '(company-files
                            (company-dabbrev-code
                             company-gtags
                             company-etags


(defun ar/python-mode-hook-function ()
  "Called when entering `python-mode'."
  (setq python-indent-offset 2)
  (python-docstring-mode +1)
  (py-yapf-enable-on-save))
(add-hook 'python-mode-hook #'ar/python-mode-hook-function)

  (setq-local company-backends '(company-go))
  (company-mode)
  (go-eldoc-setup)
  (validate-setq tab-width 2 indent-tabs-mode 1)
  (add-hook 'before-save-hook #'gofmt-before-save))

(use-package company-go :ensure t
