Bug in Stream Partial

[tharminhtet]

Adapted from cookbook cookbook.

class QuestionModel(BaseModel):
    type: str
    options: list[str]
    min: Optional[int] = None
    max: Optional[int] = None
    unit: Optional[str] = None


class ResponseModel(BaseModel):
    response: str
    question: Optional[QuestionModel] = None
    complete: bool


extraction_stream = client.chat.completions.create_partial(
    model="gpt-4o",
    response_model=ResponseModel,
    messages=[
        {
            "role": "user",
            "content": f"Get the information about the meeting and the users {text_block}",
        },
    ],
    stream=True,
)

The above works fine. But when I swapped out options: list[str] as options: Optional[list[str]]: None, I get the following.

    extraction_stream = client.chat.completions.create_partial(
  File "/Users/tharminhtet/anaconda3/lib/python3.10/site-packages/instructor/client.py", line 135, in create_partial
    response_model = instructor.Partial[response_model]  # type: ignore
  File "/Users/tharminhtet/anaconda3/lib/python3.10/site-packages/instructor/dsl/partial.py", line 300, in __class_getitem__
    **{
  File "/Users/tharminhtet/anaconda3/lib/python3.10/site-packages/instructor/dsl/partial.py", line 304, in <dictcomp>
    else _wrap_models(field_info)
  File "/Users/tharminhtet/anaconda3/lib/python3.10/site-packages/instructor/dsl/partial.py", line 273, in _wrap_models
    modified_args = tuple(
  File "/Users/tharminhtet/anaconda3/lib/python3.10/site-packages/instructor/dsl/partial.py", line 275, in <genexpr>
    Partial[arg]
  File "/Users/tharminhtet/anaconda3/lib/python3.10/site-packages/instructor/dsl/partial.py", line 300, in __class_getitem__
    **{
  File "/Users/tharminhtet/anaconda3/lib/python3.10/site-packages/instructor/dsl/partial.py", line 304, in <dictcomp>
    else _wrap_models(field_info)
  File "/Users/tharminhtet/anaconda3/lib/python3.10/site-packages/instructor/dsl/partial.py", line 273, in _wrap_models
    modified_args = tuple(
  File "/Users/tharminhtet/anaconda3/lib/python3.10/site-packages/instructor/dsl/partial.py", line 276, in <genexpr>
    if isinstance(arg, type) and issubclass(arg, BaseModel)
  File "/Users/tharminhtet/anaconda3/lib/python3.10/abc.py", line 123, in __subclasscheck__
    return _abc_subclasscheck(cls, subclass)
TypeError: issubclass() arg 1 must be a class

Wondering if this is a bug.