diff --git a/code-ch08/Chapter8.ipynb b/code-ch08/Chapter8.ipynb
index f17919ee..b49a620a 100644
--- a/code-ch08/Chapter8.ipynb
+++ b/code-ch08/Chapter8.ipynb
@@ -71,8 +71,8 @@
    "source": [
     "# Exercise 2\n",
     "\n",
-    "reload(helper.HelperTest)\n",
-    "run(helper.HelperTest.(\"test_p2pkh_address\"))"
+    "reload(helper)\n",
+    "run(helper.HelperTest(\"test_p2pkh_address\"))"
    ]
   },
   {
@@ -94,8 +94,8 @@
    "source": [
     "# Exercise 3\n",
     "\n",
-    "reload(helper.HelperTest)\n",
-    "run(helper.HelperTest.(\"test_p2sh_address\"))"
+    "reload(helper)\n",
+    "run(helper.HelperTest(\"test_p2sh_address\"))"
    ]
   },
   {
@@ -203,4 +203,4 @@
  "metadata": {},
  "nbformat": 4,
  "nbformat_minor": 2
-}
+}
\ No newline at end of file