[bug][python][pydantic]Generated from_dict() incorrectly calls List[...] as a function for nested arrays

[balazser]

Description

openapi-generator produces broken Python code when generating models with nested arrays, such as in a MultiPolygon structure.

The generated model looks like this:

class MultiPolygon(BaseModel):
    bbox: Optional[Bbox] = None
    coordinates: List[List[Annotated[List[LineStringCoordinatesInner], Field(min_length=4)]]]
    type: StrictStr

But in the generated from_dict() method, it incorrectly tries to call List[...] as a function:

"coordinates": [
    [List[LineStringCoordinatesInner].from_dict(_inner_item) for _inner_item in _item]
    for _item in obj["coordinates"]
]

Model Class

class RoofLayerFeature(geojson_pydantic.Feature):
    pass

Generated DTO class

class MultiPolygon(BaseModel):
    """
    MultiPolygon Model
    """ # noqa: E501
    bbox: Optional[Bbox] = None
    coordinates: List[List[Annotated[List[LineStringCoordinatesInner], Field(min_length=4)]]]
    type: StrictStr
    __properties: ClassVar[List[str]] = ["bbox", "coordinates", "type"]

    # ...

    @classmethod
    def from_dict(cls, obj: Optional[Dict[str, Any]]) -> Optional[Self]:
        """Create an instance of MultiPolygon from a dict"""
        if obj is None:
            return None

        if not isinstance(obj, dict):
            return cls.model_validate(obj)

        _obj = cls.model_validate({
            "bbox": Bbox.from_dict(obj["bbox"]) if obj.get("bbox") is not None else None,
            "coordinates": [
                    [List[LineStringCoordinatesInner].from_dict(_inner_item) for _inner_item in _item]
                    for _item in obj["coordinates"]
                ] if obj.get("coordinates") is not None else None,
            "type": obj.get("type")
        })
        return _obj

This leads to a runtime error since List[...] is not callable.
openapi-generator version

@openapitools/[email protected]

Steps to Reproduce

Generate a Python client using a schema that includes a deeply nested array (like MultiPolygon) and try to use the generated from_dict() method. It will fail due to misuse of List[...] as a constructor.

Currently I'm using fastapi + https://github.com/developmentseed/geojson-pydantic