Setting `()` to `Union`, which means no type arguments doesn't get error

[hyperkai]

*Memo:

• pyright test.py
• pyright 1.1.408
• Python 3.14.0

The error message caused by Union with one type says as shown below:

from typing import Union

v: Union[int] # Error

error: Union requires two or more type arguments (reportInvalidTypeArguments

But setting () to Union, which means no type arguments doesn't get error as shown below:

from typing import Union

v: Union[()] # No error