diff --git a/introduction/02_introduction_to_python_2.ipynb b/introduction/02_introduction_to_python_2.ipynb
index dc6ee491a63fe15bb261f8349dcbc68a2df15e1f..4ea943136d36ca5164fb6b75366ea3c10102ef6c 100644
--- a/introduction/02_introduction_to_python_2.ipynb
+++ b/introduction/02_introduction_to_python_2.ipynb
@@ -1678,6 +1678,20 @@
     "There are many more useful iterables in Python."
    ]
   },
+  {
+   "cell_type": "markdown",
+   "metadata": {
+    "slideshow": {
+     "slide_type": "slide"
+    }
+   },
+   "source": [
+    "Homework assignment\n",
+    "===\n",
+    "\n",
+    "https://classroom.github.com/a/QU2iPYKn"
+   ]
+  },
   {
    "cell_type": "markdown",
    "metadata": {
diff --git a/introduction/02_introduction_to_python_3.ipynb b/introduction/02_introduction_to_python_3.ipynb
index 1e1968db90096e68fcd3c53c448ae0c2c619c0e6..53cc781e5ade3ba67a9c84f7c83b856c90bba1e7 100644
--- a/introduction/02_introduction_to_python_3.ipynb
+++ b/introduction/02_introduction_to_python_3.ipynb
@@ -23,10 +23,13 @@
     "Functions\n",
     "===\n",
     "\n",
+    "A _function_ is a named sequence of statements that performs some piece of work.\n",
+    "Later on that function can be called by using its name.\n",
+    "\n",
     "Defining a function\n",
     "---\n",
     "\n",
-    "A function definition includes its name, arguments and body."
+    "A function definition includes its _name_, _arguments_ and _body_."
    ]
   },
   {