diff --git a/utils.rkt b/utils.rkt
index f363f25..003a454 100644
--- a/utils.rkt
+++ b/utils.rkt
@@ -16,7 +16,7 @@
                [stringify-variable-mapping (-> variable-mapping? string-variable-mapping?)]
                [string->any (-> string? any/c)]
                [read-org-table (-> string? (listof any/c))]
-               [unstringify-pairs (-> (listof (general-pair/c string? string?))
+               [unstringify-pairs (-> (listof (general-pair/c string? any/c))
                                       (listof (general-pair/c symbol? any/c)))]
                [read-org-variable-mapping (-> string? variable-mapping?)]
                [update-vertices/unweighted (-> graph? (-> any/c any/c) graph?)])
@@ -183,16 +183,21 @@
   (or/c (list/c key-contract val-contract)
         (cons/c key-contract val-contract)))
 
-;;; Given a list of pairs of strings, converts the first element of
-;;; each pair to a string, and reads the second element with
-;;; string->any.
+;;; Given a list of pairs of strings and some other values (possibly
+;;; strings), converts the first element of each pair to a string, and
+;;; reads the second element with string->any or keeps it as is if it
+;;; is not a string.
 (define (unstringify-pairs pairs)
   (for/list ([p pairs])
     (match p
       [(list key val)
-       (cons (string->symbol key) (string->any val))]
+       (cons (string->symbol key) (if (string? val)
+                                      (string->any val)
+                                      val))]
       [(cons key val)                   ; also handle improper pairs
-       (cons (string->symbol key) (string->any val))])))
+       (cons (string->symbol key) (if (string? val)
+                                      (string->any val)
+                                      val))])))
 
 ;;; Reads a variable mapping from a string, such as the one which
 ;;; Org-mode produces from tables.