updated bokeh solution notebook

4_PlottingData.ipynb

@@ -2637,7 +2637,7 @@
    "cell_type": "markdown",
    "metadata": {},
    "source": [
-    "After you have finished on this exercise, or if you get really stuck and need to look at a solution, take a look at [this notebook](http://nbviewer.ipython.org/github/tobyhodges/ITPP/tree/master/Exercise4_7WalkthroughBokeh.ipynb), which runs through my way of producing the site plots with a different bar color for each taxon."
+    "After you have finished on this exercise, or if you get really stuck and need to look at a solution, take a look at [this notebook](http://nbviewer.ipython.org/github/tobyhodges/ITPP/tree/master/Exercise4_9WalkthroughBokeh.ipynb), which runs through my way of producing the site plots with a different bar color for each taxon."
    ]
   },
   {