message: Small fix for an eager colab notebook.
diff: "source": [
  "# Time GPU-based matrix multiplications.\n",
  "\n",
  - "if is_gpu_available:\n",
  + "if tf.test.is_gpu_available():\n",
  " # First use of the GPU will be slow:\n",
  " print(\"Time to conduct first matmul on GPU:\")\n",
  " %time tf.matmul(gpu_tensor, gpu_tensor)\n",
  