Update query_cellar_python.ipynb

Author: duprijil

notebooks/query_cellar_python.ipynb

@@ -4,6 +4,8 @@
    "cell_type": "markdown",
    "source": [
     "## This example show how to query sparql endpoint using Python.\n",
+    "\n",
+    "### This example assumes that a python interpreter and jupyter notebook is already installed\n",
     "### To run this, press \"Run all\" button, or Ctrl+Shift+Alt+Enter"
    ],
    "metadata": {