Better upload error handling.

samples/outreach/blogs/segmentation_blogpost/image_segmentation.ipynb

@@ -144,9 +144,22 @@
       "cell_type": "markdown",
       "source": [
         "# Get all the files \n",
-        "Since this tutorial will be using a dataset from Kaggle, it requires [creating an API Token](https://github.com/Kaggle/kaggle-api) for your Kaggle acccount, and uploading it. "
+        "Since this tutorial will be using a dataset from Kaggle, it requires [creating an API Token](https://github.com/Kaggle/kaggle-api#api-credentials) for your Kaggle acccount, and uploading it. "
       ]
     },
+    {
+      "metadata": {
+        "id": "7jgdraTAiti0",
+        "colab_type": "code",
+        "colab": {}
+      },
+      "cell_type": "code",
+      "source": [
+        "rm /content/.kaggle/kaggle.json\n"
+      ],
+      "execution_count": 0,
+      "outputs": []
+    },
     {
       "metadata": {
         "id": "sAVM1ZTmdAMR",
@@ -173,7 +186,11 @@
         "      raise no_file\n",
         "    \n",
         "    uploaded = files.upload()\n",
-        "    with open(token_file, \"w\") as f:\n",
+        "    \n",
+        "    if \"kaggle.json\" not in uploaded:\n",
+        "      raise ValueError(\"You need an API key! see: \"\n",
+        "                       \"https://github.com/Kaggle/kaggle-api#api-credentials\")\n",
+        "    with open(token_file, \"wb\") as f:\n",
         "      f.write(uploaded[\"kaggle.json\"])\n",
         "    os.chmod(token_file, 600)\n",
         "\n",