diff --git a/test/test-helper.el b/test/test-helper.el
index c400d48..b63296b 100644
--- a/test/test-helper.el
+++ b/test/test-helper.el
@@ -114,23 +114,6 @@
 Set the value of this variable at the beginning of each test that uses
 it.")
 
-(unless (fboundp 'hash-table-keys)
-  (defun hash-table-keys (hash-table)
-    "Return a list of keys in HASH-TABLE."
-    (let (result)
-      (maphash (lambda (key value)
-                 (setq result (append (list key) result)))
-               hash-table)
-      result))
-
-  (defun hash-table-values (hash-table)
-    "Return a list of values in HASH-TABLE."
-    (let (result)
-      (maphash (lambda (key value)
-                 (setq result (append (list value) result)))
-               hash-table)
-      result)))
-
 (defmacro purpose-with-empty-config (&rest body)
   (declare (indent defun) (debug body))
   `(let ((purpose--user-mode-purposes (make-hash-table))
diff --git a/window-purpose-core.el b/window-purpose-core.el
index c4cca1f..84aee97 100644
--- a/window-purpose-core.el
+++ b/window-purpose-core.el
@@ -80,8 +80,7 @@ mode and MODE-CONF.
 MODE-CONF is a hash table mapping modes to purposes."
   (when (get-buffer buffer-or-name)     ; check if buffer exists
     (let* ((major-mode (purpose--buffer-major-mode buffer-or-name))
-           (derived-modes (purpose--iter-hash (lambda (mode &optional _) mode)
-                                              mode-conf))
+           (derived-modes (hash-table-keys mode-conf))
            (derived-mode (apply #'derived-mode-p derived-modes)))
       (when derived-mode
         (gethash derived-mode mode-conf)))))
diff --git a/window-purpose-utils.el b/window-purpose-utils.el
index 752027a..8c9e0dc 100644
--- a/window-purpose-utils.el
+++ b/window-purpose-utils.el
@@ -100,15 +100,6 @@ Example:
 
 
 
-(defun purpose--iter-hash (function table)
-  "Like `maphash', but return a list the results of calling FUNCTION
-for each entry in hash-table TABLE."
-  (let (results)
-    (maphash (lambda (key value)
-               (push (funcall function key value) results))
-             table)
-    results))
-
 ;; taken from http://emacs.stackexchange.com/a/7405/6533, credit to Jordon Biondo
 (defun purpose--call-stack ()
   "Return the current call stack frames."