Toggle appointment notification

[pietru]

Want to toggle between enable and disable appointment notification and have
put a defun as so below.  I reckon that both  appt-activate and appt-check
are needed but not absolutely aware of what and how they activate things
for appointments.

What would be a right approach to toggle between enable and disable using
a single key-sequence for my case here?

(defun diary-appt-ntf (n)
   "Switches diary appointment notification."

   (appt-activate n)  ; Activates diary appointment notification

   (if (< n 1)
     (appt-check 1)    ; Checks appointments and updates reminders.
     (appt-check nil)) ; Disables appt-check
)