fix demo8

Author: dnjohnstone

08 Pair Distribution Function Analysis.ipynb

@@ -71,7 +71,7 @@
    "metadata": {},
    "outputs": [],
    "source": [
-    "%matplotlib tk\n",
+    "%matplotlib qt\n",
     "import pyxem as pxm\n",
     "import numpy as np"
    ]
@@ -425,15 +425,6 @@
     "pdf = pdfgen.get_pdf(s_min=s_min, s_max=s_max, r_max=10)"
    ]
   },
-  {
-   "cell_type": "code",
-   "execution_count": null,
-   "metadata": {},
-   "outputs": [],
-   "source": [
-    "pdf"
-   ]
-  },
   {
    "cell_type": "code",
    "execution_count": null,