Show error if STATUS isn't one of the accepted values

tekuti.el

@@ -65,6 +65,12 @@ with a ‘/’.")
      (list "COMMENTS-CLOSED-DATE"
            (and (not (string-empty-p date))
                 (tekuti--format-date date))))
+    (`("STATUS" ,status)
+     (let ((accepted-values '("publish" "draft" "private")))
+       (if (member status accepted-values)
+           pair
+         (error "Unknown post status: %s; Accepted values are: %s"
+                status accepted-values))))
     (_ pair)))
 
 (defun tekuti-build-data-from-org ()