# Cannot load Hello World

**URL:** <https://forums.developer.nvidia.com/t/cannot-load-hello-world/256415>\
**Category:** Isaac Sim\
**Created:** [June 12, 2023, 5:30pm UTC](https://forums.developer.nvidia.com/t/cannot-load-hello-world/256415 "2023-06-12T17:30:16Z")\
**Posts on this page:** 2\
**Page:** 1

<div class="post-metadata">

**Author:** ![candy.lin](https://developer.download.nvidia.com/images/forums/profile-default-devtalk-84.png) [@candy.lin](https://forums.developer.nvidia.com/u/candy.lin)\
**Post date:** [June 12, 2023, 5:30pm UTC](https://forums.developer.nvidia.com/t/cannot-load-hello-world/256415/1 "2023-06-12T17:30:16Z")

</div>

This is the error I get when trying to load Hello World  
Using Isaac Sim 2022.2.1

```auto
2023-06-12 17:29:23 [42,131ms] [Error] [asyncio] Task exception was never retrieved
future: <Task finished coro=<BaseSampleExtension._on_load_world.<locals>._on_load_world_async() done, defined at c:\users\linca\appdata\local\ov\pkg\isaac_sim-2022.2.1\exts\omni.isaac.examples\omni\isaac\examples\base_sample\base_sample_extension.py:150> exception=AttributeError("'NoneType' object has no attribute 'GetPath'")>
Traceback (most recent call last):
  File "c:\users\linca\appdata\local\ov\pkg\isaac_sim-2022.2.1\exts\omni.isaac.examples\omni\isaac\examples\base_sample\base_sample_extension.py", line 151, in _on_load_world_async
    await self._sample.load_world_async()
  File "c:\users\linca\appdata\local\ov\pkg\isaac_sim-2022.2.1\exts\omni.isaac.examples\omni\isaac\examples\base_sample\base_sample.py", line 43, in load_world_async
    self.setup_scene()
  File "c:\users\linca\appdata\local\ov\pkg\isaac_sim-2022.2.1\exts\omni.isaac.examples\omni\isaac\examples\hello_world\hello_world.py", line 22, in setup_scene
    world.scene.add_default_ground_plane()
  File "c:\users\linca\appdata\local\ov\pkg\isaac_sim-2022.2.1\exts\omni.isaac.core\omni\isaac\core\scenes\scene.py", line 223, in add_default_ground_plane
    plane = GroundPlane(prim_path=prim_path, name=name, z_position=z_position, physics_material=physics_material)
  File "c:\users\linca\appdata\local\ov\pkg\isaac_sim-2022.2.1\exts\omni.isaac.core\omni\isaac\core\objects\ground_plane.py", line 94, in __init__
    get_first_matching_child_prim(prim_path=prim_path, predicate=lambda x: get_prim_type_name(x) == "Plane")
  File "c:\users\linca\appdata\local\ov\pkg\isaac_sim-2022.2.1\exts\omni.isaac.core\omni\isaac\core\utils\prims.py", line 304, in get_prim_path
    return prim.GetPath().pathString
AttributeError: 'NoneType' object has no attribute 'GetPath'

```

---

<div class="post-metadata">

**Author:** ![rthaker](https://sea2.discourse-cdn.com/nvidia/user_avatar/forums.developer.nvidia.com/rthaker/32/171374_2.png) [@rthaker](https://forums.developer.nvidia.com/u/rthaker)\
**Post date:** [June 29, 2023, 9:07pm UTC](https://forums.developer.nvidia.com/t/cannot-load-hello-world/256415/2 "2023-06-29T21:07:14Z")

</div>

Hi @candy.lin - It seems that code is trying to call the `GetPath` method on object that is `None` . This usually happens when property of an object is accessed before it has been properly initialized.

In your case, `prim` object is `None` when code is trying to call `prim.Gethpath().pathString`. This could be because the `get_first_matching_child_prim` function didn’t find a matching child prim and returned `None` .

Please check following things:

1. Make sure that the `prim_path` argument you’re passing to the `GroundPlane` constructor is correct.
2. The `get_first_matching_child_prim` function uses a predicate function to find the first child prim that matches certain criteria. In this case, it’s looking for a prim with a type name of “Plane”. Make sure that there is a prim in your scene that matches this criteria.
3. Modify your code to handle the case where `get_first_matching_child_prim` returns `None` . You can do this by checking if `prim` is `None` before trying to call `GetPath` on it.