diff --git a/arrays_strings/two_sum/two_sum_challenge.ipynb b/arrays_strings/two_sum/two_sum_challenge.ipynb
index 733b9ec..b482418 100644
--- a/arrays_strings/two_sum/two_sum_challenge.ipynb
+++ b/arrays_strings/two_sum/two_sum_challenge.ipynb
@@ -87,7 +87,7 @@
    "source": [
     "class Solution(object):\n",
     "\n",
-    "    def two_sum(self, val):\n",
+    "    def two_sum(self, nums, val):\n",
     "        # TODO: Implement me\n",
     "        pass"
    ]