Update: filename verification

Author: jackdmarquez

hands-on/session II/2.Explore_Data.ipynb

@@ -56,6 +56,9 @@
    "source": [
     "# Change the name of data file with the name of your downloaded subregion\n",
     "data_file = \"enter_the_name.here\"\n",
+    "\n",
+    "assert os.path.isfile(data_file), f\"Error: The file '{data_file}' does not exist.\"\n",
+    "\n",
     "print(\"You have successfully defined the name of the file\")\n"
    ]
   },
@@ -379,7 +382,7 @@
    "name": "python",
    "nbconvert_exporter": "python",
    "pygments_lexer": "ipython3",
-   "version": "3.11.11"
+   "version": "3.10.14"
   }
  },
  "nbformat": 4,