diff --git a/happypose_msgs/examples/meshcat_viz.ipynb b/happypose_msgs/examples/meshcat_viz.ipynb
index fc09f59..57bff9a 100644
--- a/happypose_msgs/examples/meshcat_viz.ipynb
+++ b/happypose_msgs/examples/meshcat_viz.ipynb
@@ -28,7 +28,7 @@
     "\n",
     "python_version = f\"python{sys.version_info.major}.{sys.version_info.minor}\"\n",
     "dist_package_path = Path(\"local\") / \"lib\" / python_version / \"dist-packages\"\n",
-    "ros_path = Path(\"/opt\") / \"ros\" / os.environ['ROS_DISTRO'] / dist_package_path\n",
+    "ros_path = Path(\"/opt\") / \"ros\" / os.environ[\"ROS_DISTRO\"] / dist_package_path\n",
     "colson_ws_path = my_colcon_ws_path / \"install\" / \"happypose_msgs\" / dist_package_path\n",
     "sys.path.append(ros_path.as_posix())\n",
     "sys.path.append(colson_ws_path.as_posix())"