[BUG][Python] Model template doesn't properly handle nested dicts and arrays.

Bug Report Checklist

• Have you provided a full/minimal spec to reproduce the issue?
• Have you validated the input using an OpenAPI validator?
• Have you tested with the latest master to confirm the issue still exists?
• Have you searched for related issues/PRs?
• What's the actual output vs expected output?
• [Optional] Sponsorship to speed up the bug fix or feature request (example)

Description

I have some components that contain dicts of dicts. With the default templates the generator doesn't generate valid python-code for these components.

Here is the generated code: https://gist.github.com/ottmar-zittlau/9d2d98ffd9b29c3bcb34b9e947228354

Some bugs:

Here the class on which from_dict is called is a type.

"array_of_dictionaries": [Dict[str, Vector3d].from_dict(_item) for _item in obj["array_of_dictionaries"]] if obj.get("array_of_dictionaries") is not None else None,

Here _item_array_of_dictionaries is a dictionary that doesn't have a to_dict method.

        if self.array_of_dictionaries:
            for _item_array_of_dictionaries in self.array_of_dictionaries:
                if _item_array_of_dictionaries:
                    _items.append(_item_array_of_dictionaries.to_dict())
            _dict['array_of_dictionaries'] = _items

openapi-generator version

7.16.0

OpenAPI declaration file content or url

https://gist.github.com/ottmar-zittlau/2e2a5357b1d1e60d41a2aef4ee6bde14

Generation Details

I generated code for python.

Steps to reproduce

Run

./openapi-generator-cli generate --generator-name python --input-spec openapi.yaml --output generated --package-name example

Related issues/PRs

Suggest a fix

I already have adapted the model_generic.mustache template file to deal with this, but before opening a merge request I wanted to know if this bug is known and whether there is already work going on to fix it.

Start with the Python generator's model_generic.mustache template and the OpenAPI declaration linked in the issue. Run the provided openapi-generator-cli command to reproduce the generated code shown in the gist, then verify that nested dictionaries and arrays produce valid Python conversion code without calling from_dict or to_dict on plain dictionaries.