diff --git a/code-ch05/Chapter5.ipynb b/code-ch05/Chapter5.ipynb
index 16f1aaf1..ae43b0c6 100644
--- a/code-ch05/Chapter5.ipynb
+++ b/code-ch05/Chapter5.ipynb
@@ -193,6 +193,7 @@
    "source": [
     "# Exercise 6\n",
     "\n",
+    "import tx\n",
     "reload(tx)\n",
     "run(tx.TxTest(\"test_fee\"))"
    ]