removed temporary export fix

Author: TannerGilbert

Diff for: README.md

@@ -256,8 +256,6 @@ The training script saves checkpoints about every five minutes. Train the model
 
 Now that we have a trained model, we need to generate an inference graph that can be used to run the model.
 
-> Note: There is currently an [issue](https://github.com/tensorflow/models/issues/8841) that occurs when you're trying to export the model. As a temporary fix, Github user [Jacobsolawetz](https://github.com/Jacobsolawetz) discovered that you can add ```if not isinstance(x, str):``` add line 140 of the ```https://github.com/tensorflow/tensorflow/blob/master/tensorflow/python/keras/utils/tf_utils.py``` script. For more information, check out [his comment on the issue](https://github.com/tensorflow/models/issues/8841#issuecomment-657647648).
-
 ```bash
 python /content/models/research/object_detection/exporter_main_v2.py \
     --trained_checkpoint_dir training \

Diff for: Tensorflow_2_Object_Detection_Train_model.ipynb

@@ -2325,50 +2325,6 @@
         "## Export model inference graph"
       ]
     },
-    {
-      "cell_type": "markdown",
-      "metadata": {
-        "id": "6rYr6VKH8_QU",
-        "colab_type": "text"
-      },
-      "source": [
-        "The below code cell adds a line to the tf_utils.py file. This is a temporary fix to a [exporting issue](https://github.com/tensorflow/models/issues/8841) occuring when using the OD API with Tensorflow 2. This code will be removed as soon as the OD Team puts out a fix.\n",
-        "\n",
-        "All credit goes to Github user [Jacobsolawetz](https://github.com/Jacobsolawetz), who provided this [temporary fix](https://github.com/tensorflow/models/issues/8841#issuecomment-657647648)."
-      ]
-    },
-    {
-      "cell_type": "code",
-      "metadata": {
-        "id": "Usv5FMT1xG1L",
-        "colab_type": "code",
-        "colab": {
-          "base_uri": "https://localhost:8080/",
-          "height": 34
-        },
-        "outputId": "a51d45a9-c90f-4b78-e323-8a6c69217f7f"
-      },
-      "source": [
-        "with open('/usr/local/lib/python3.6/dist-packages/tensorflow/python/keras/utils/tf_utils.py') as f:\n",
-        "    tf_utils = f.read()\n",
-        "\n",
-        "with open('/usr/local/lib/python3.6/dist-packages/tensorflow/python/keras/utils/tf_utils.py', 'w') as f:\n",
-        "  # Set labelmap path\n",
-        "  throw_statement = \"raise TypeError('Expected Operation, Variable, or Tensor, got ' + str(x))\"\n",
-        "  tf_utils = tf_utils.replace(throw_statement, \"if not isinstance(x, str):\" + throw_statement)\n",
-        "  f.write(tf_utils)"
-      ],
-      "execution_count": 22,
-      "outputs": [
-        {
-          "output_type": "stream",
-          "text": [
-            "Overwriting /usr/local/lib/python3.6/dist-packages/tensorflow/python/keras/utils/tf_utils.py\n"
-          ],
-          "name": "stdout"
-        }
-      ]
-    },
     {
       "cell_type": "code",
       "metadata": {