While handling marshmallow ValidationError containing other ValidationError(s), make_response fails about apiflask HOT 5 OPEN

from apiflask import APIFlask
from marshmallow_dataclass import dataclass

app = APIFlask(__name__)


@dataclass
class Req:
    var1: int | str


@app.post("/")
@app.input(Req.Schema)
def index():
    return {"message": "lol"}

flask --app test:app run

curl http://127.0.0.1:5000 -H 'Content-Type: application/json' -d '{"var1": true}'

* Serving Flask app 'test:app'
 * Debug mode: off
WARNING: This is a development server. Do not use it in a production deployment. Use a production WSGI server instead.
 * Running on http://127.0.0.1:5000
Press CTRL+C to quit
[2024-02-05 12:37:31,799] ERROR in app: Exception on / [POST]
Traceback (most recent call last):
  File "/Users/tarun/workspace/feature-foundation/venv/lib/python3.11/site-packages/flask/app.py", line 2528, in wsgi_app
    response = self.full_dispatch_request()
               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/tarun/workspace/feature-foundation/venv/lib/python3.11/site-packages/flask/app.py", line 1826, in full_dispatch_request
    return self.finalize_request(rv)
           ^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/tarun/workspace/feature-foundation/venv/lib/python3.11/site-packages/flask/app.py", line 1845, in finalize_request
    response = self.make_response(rv)
               ^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/tarun/workspace/feature-foundation/venv/lib/python3.11/site-packages/flask/app.py", line 2156, in make_response
    rv = self.json.response(rv)
         ^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/tarun/workspace/feature-foundation/venv/lib/python3.11/site-packages/flask/json/provider.py", line 309, in response
    f"{self.dumps(obj, **dump_args)}\n", mimetype=mimetype
       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/tarun/workspace/feature-foundation/venv/lib/python3.11/site-packages/flask/json/provider.py", line 230, in dumps
    return json.dumps(obj, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/homebrew/Cellar/[email protected]/3.11.4_1/Frameworks/Python.framework/Versions/3.11/lib/python3.11/json/__init__.py", line 238, in dumps
    **kw).encode(obj)
          ^^^^^^^^^^^
  File "/opt/homebrew/Cellar/[email protected]/3.11.4_1/Frameworks/Python.framework/Versions/3.11/lib/python3.11/json/encoder.py", line 200, in encode
    chunks = self.iterencode(o, _one_shot=True)
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/homebrew/Cellar/[email protected]/3.11.4_1/Frameworks/Python.framework/Versions/3.11/lib/python3.11/json/encoder.py", line 258, in iterencode
    return _iterencode(o, 0)
           ^^^^^^^^^^^^^^^^^
  File "/Users/tarun/workspace/feature-foundation/venv/lib/python3.11/site-packages/flask/json/provider.py", line 122, in _default
    raise TypeError(f"Object of type {type(o).__name__} is not JSON serializable")
TypeError: Object of type ValidationError is not JSON serializable
127.0.0.1 - - [05/Feb/2024 12:37:31] "POST / HTTP/1.1" 500 -