diff --git a/lib/fpkg.el b/lib/fpkg.el
index 6b68a51..a6fd8c9 100644
--- a/lib/fpkg.el
+++ b/lib/fpkg.el
@@ -91,18 +91,10 @@
 
 (defun fg42-install-extension (args)
   (let ((extension-name (get-extension-name args)))
-    (if (is-official-extension extension-name)
-        (straight-use-package (get-official-extension-receipe extension-name))
-      (straight-use-package extension-name))))
-
-(defun extensionp (args)
-  "Tell if given ARGS is a FG42 extension or a normal straight package."
-  (cond
-   ((symbolp args) (string= (car (last (split-string (symbol-name args) "-"))) "extension"))
-   ((listp args) (string= (car (last (split-string (symbol-name (car args)) "-"))) "extension"))))
+    (straight-use-package (get-official-extension-receipe extension-name))))
 
 (defun depends-on (args)
-  (if (extensionp args)
+  (if (is-official-extension args)
       (fg42-install-extension args)
     (straight-use-package args)))