Made hands-on part a slide in 2nd introduction lecture.

introduction/02_introduction_to_python_2.ipynb

@@ -1692,7 +1692,11 @@
   },
   {
    "cell_type": "markdown",
-   "metadata": {},
+   "metadata": {
+    "slideshow": {
+     "slide_type": "slide"
+    }
+   },
    "source": [
     "<div class=\"alert alert-success\">\n",
     "<h1>Hands on!</h1>\n",