Pyright diagnostic type incompatible

```python
@magics_class
class SimpleGPTMagics(Magics):
api_type = Unicode("openai", help="The type of api that will be used to query the models").tag(config=True)

```
[pyright](https://microsoft.github.io/pyright/) report
```
Diagnostics:
1. Argument of type "Literal['openai']" cannot be assigned to parameter "default_value" of type "Sentinel" in function "__init__"
  "Literal['openai']" is incompatible with "Sentinel" [reportGeneralTypeIssues]

```

https://github.com/ipython/traitlets/blob/05d6ecb6b1f90736cdeacf41c7d5e84b147c1dbd/traitlets/traitlets.py#L479-L497

https://github.com/ipython/traitlets/blob/05d6ecb6b1f90736cdeacf41c7d5e84b147c1dbd/traitlets/traitlets.py#L135-L141

Obviously, the argument of `TraitType.__init__`, `default_vaue` is infered to `Sentinel`, what can I do to suppress the diagnostic?