TypeError: Object of type Assignment is not JSON serializable — в чём может быть ошибка?

Всем привет! :) Я пытаюсь вывести домашнее задание урока с помощью NetSchoolAPI, но выходит вот такая ошибка:

Traceback (most recent call last):
  File "C:\Users\79170\Desktop\ProjectTwo\netschool.py", line 34, in <module>
    asyncio.run(main())
  File "C:\Users\79170\AppData\Local\Programs\Python\Python310\lib\asyncio\runners.py", line 44, in run
    return loop.run_until_complete(main)
  File "C:\Users\79170\AppData\Local\Programs\Python\Python310\lib\asyncio\base_events.py", line 649, in run_until_complete
    return future.result()
  File "C:\Users\79170\Desktop\ProjectTwo\netschool.py", line 23, in main
    attachments = await ns.attachments(assignment)
  File "C:\Users\79170\Desktop\ProjectTwo\venv\lib\site-packages\netschoolapi\netschoolapi.py", line 254, in attachments
    self._wrapped_client.client.build_request(
  File "C:\Users\79170\Desktop\ProjectTwo\venv\lib\site-packages\httpx\_client.py", line 360, in build_request
    return Request(
  File "C:\Users\79170\Desktop\ProjectTwo\venv\lib\site-packages\httpx\_models.py", line 339, in __init__
    headers, stream = encode_request(
  File "C:\Users\79170\Desktop\ProjectTwo\venv\lib\site-packages\httpx\_content.py", line 215, in encode_request
    return encode_json(json)
  File "C:\Users\79170\Desktop\ProjectTwo\venv\lib\site-packages\httpx\_content.py", line 178, in encode_json
    body = json_dumps(json).encode("utf-8")
  File "C:\Users\79170\AppData\Local\Programs\Python\Python310\lib\json\__init__.py", line 231, in dumps
    return _default_encoder.encode(obj)
  File "C:\Users\79170\AppData\Local\Programs\Python\Python310\lib\json\encoder.py", line 199, in encode
    chunks = self.iterencode(o, _one_shot=True)
  File "C:\Users\79170\AppData\Local\Programs\Python\Python310\lib\json\encoder.py", line 257, in iterencode
    return _iterencode(o, 0)
  File "C:\Users\79170\AppData\Local\Programs\Python\Python310\lib\json\encoder.py", line 179, in default
    raise TypeError(f'Object of type {o.__class__.__name__} '
TypeError: Object of type Assignment is not JSON serializable

Вот сам код:

import asyncio
from netschoolapi import NetSchoolAPI

async def main():

    # Создаём клиент. Через него мы будем обращаться
    # к АПИ электронного дневника
    ns = NetSchoolAPI('https://net-school.cap.ru/')

    # Логинимся в "Сетевой город"
    await ns.login(
        '', #Логин ученика
        '', #Пароль ученика
        511, #id Школы
    )

    diary = await ns.diary()
    for day in diary.schedule:
        for lesson in day.lessons:
            for assignment in lesson.assignments:
                attachments = await ns.attachments(assignment)
                if attachments:
                    print(
                        f"Some attachments found on day {day.day} on "
                        f"{lesson.subject} homework: {attachments}"
                    )

    await ns.logout()

if __name__ == '__main__':
    asyncio.run(main())