diff --git a/sorting_searching/insertion_sort/insertion_sort_challenge.ipynb b/sorting_searching/insertion_sort/insertion_sort_challenge.ipynb
index f046ff8..eabd38a 100644
--- a/sorting_searching/insertion_sort/insertion_sort_challenge.ipynb
+++ b/sorting_searching/insertion_sort/insertion_sort_challenge.ipynb
@@ -82,7 +82,7 @@
    "source": [
     "class InsertionSort(object):\n",
     "\n",
-    "    def sort(data):\n",
+    "    def sort(self, data):\n",
     "        # TODO: Implement me\n",
     "        pass"
    ]