meta key switch

mac-switch-meta.el

;; Keybonds
(global-set-key [(hyper a)] 'mark-whole-buffer)
(global-set-key [(hyper v)] 'yank)
(global-set-key [(hyper c)] 'kill-ring-save)
(global-set-key [(hyper s)] 'save-buffer)
(global-set-key [(hyper l)] 'goto-line)
(global-set-key [(hyper w)]
                (lambda () (interactive) (delete-window)))
(global-set-key [(hyper z)] 'undo)

;; mac switch meta key
(defun mac-switch-meta nil 
  "switch meta between Option and Command"
  (interactive)
  (if (eq mac-option-modifier nil)
      (progn
	(setq mac-option-modifier 'meta)
	(setq mac-command-modifier 'hyper)
	)
    (progn 
      (setq mac-option-modifier nil)
      (setq mac-command-modifier 'meta)
      )
    )
  )

I am sorry, but how do you use this?
I included the contents of the file in the beginning of this thread in my setup but I still can't have them swapped.
I am on Catalina by the way. I am also using terminal mode (emacs -nw)

@hisnawi This setup does not work for emacs -nw, since it is your terminal emulator(iTerm2, Terminal.app etc) who controls the cmd and option key behavior.