(let* ((subkeymap (key-binding prefix))
(ua-keys (where-is-internal 'universal-argument nil t))
(prefix-string (notmuch-prefix-key-description prefix))
(let* ((subkeymap (key-binding prefix))
(ua-keys (where-is-internal 'universal-argument nil t))
(prefix-string (notmuch-prefix-key-description prefix))