TypeError：类型Coroutine的对象不是JSON序列化的

Question

我最近对日期转换功能有问题。

代码本身与Telegram Core API一起使用，应从我需要的频道接收消息。该函数本身似乎可以正常工作，除了代码序列化的代码部分，此错误发生了：

Unhandled exception on list
Traceback (most recent call last):
  File "C:\Users\79607\AppData\Local\Programs\Python\Python310\lib\site-packages\telethon\client\updates.py", line 467, in _dispatch_update
    await callback(event)
  File "E:\freelance\bot_admin\launch2.py", line 83, in list
    await dump_all_messages( channel )
  File "E:\freelance\bot_admin\launch2.py", line 74, in dump_all_messages
    json.dump(all_messages, outfile, ensure_ascii=False, cls=DateTimeEncoder)
  File "C:\Users\79607\AppData\Local\Programs\Python\Python310\lib\json\__init__.py", line 179, in dump
    for chunk in iterable:
  File "C:\Users\79607\AppData\Local\Programs\Python\Python310\lib\json\encoder.py", line 429, in _iterencode
    yield from _iterencode_list(o, _current_indent_level)
  File "C:\Users\79607\AppData\Local\Programs\Python\Python310\lib\json\encoder.py", line 325, in _iterencode_list
    yield from chunks
  File "C:\Users\79607\AppData\Local\Programs\Python\Python310\lib\json\encoder.py", line 405, in _iterencode_dict
    yield from chunks
  File "C:\Users\79607\AppData\Local\Programs\Python\Python310\lib\json\encoder.py", line 405, in _iterencode_dict
    yield from chunks
  File "C:\Users\79607\AppData\Local\Programs\Python\Python310\lib\json\encoder.py", line 325, in _iterencode_list
    yield from chunks
  File "C:\Users\79607\AppData\Local\Programs\Python\Python310\lib\json\encoder.py", line 405, in _iterencode_dict
    yield from chunks
  File "C:\Users\79607\AppData\Local\Programs\Python\Python310\lib\json\encoder.py", line 325, in _iterencode_list
    yield from chunks
  File "C:\Users\79607\AppData\Local\Programs\Python\Python310\lib\json\encoder.py", line 405, in _iterencode_dict
    yield from chunks
  File "C:\Users\79607\AppData\Local\Programs\Python\Python310\lib\json\encoder.py", line 439, in _iterencode
    yield from _iterencode(o, _current_indent_level)
  File "C:\Users\79607\AppData\Local\Programs\Python\Python310\lib\json\encoder.py", line 438, in _iterencode
    o = _default(o)
  File "E:\freelance\bot_admin\launch2.py", line 49, in default
    return json.JSONEncoder.default(self, o)
  File "C:\Users\79607\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 coroutine is not JSON serializable

这是我目前所拥有的所有代码：

import configparser
import json
import datetime

from telethon.sync import TelegramClient , events
from telethon import connection


from datetime import date, datetime


from telethon.tl.functions.channels import GetParticipantsRequest
from telethon.tl.types import ChannelParticipantsSearch


from telethon.tl.functions.messages import GetHistoryRequest


config = configparser.ConfigParser()
config.read("config.ini")


api_id   = config['Telegram']['api_id']
api_hash = config['Telegram']['api_hash']
username = config['Telegram']['username']
bot__token = config['Telegram']['bot_token']

client = TelegramClient( username, api_id, api_hash )
bot = TelegramClient( 'bot' , api_id , api_hash ).start( bot_token = bot__token )


current_action = ''

async def dump_all_messages(channel):
    offset_msg = 0 
    limit_msg = 100
    
    all_messages = []
    total_messages = 0
    total_count_limit = 2
    
    class DateTimeEncoder(json.JSONEncoder):
        
        def default(self, o):
            if isinstance(o, datetime):
                return o.isoformat()
            if isinstance(o, bytes):
                return list(o)
            return json.JSONEncoder.default(self, o)
                
    while True:
        history = await client( GetHistoryRequest (
                peer=channel,
                offset_id=offset_msg,
                offset_date=None,
                add_offset=0,
                limit=limit_msg, 
                max_id=0, 
                min_id=0,
                hash=0
            )
        )
        if not history.messages:
            break
        messages = history.messages
        for message in messages:
            all_messages.append(message.to_dict())
        offset_msg = messages[len(messages) - 1].id
        total_messages = len(all_messages)
        if total_count_limit != 0 and total_messages >= total_count_limit:
            break
        
    with open('channel_messages.json', 'w', encoding='utf8') as outfile:
        json.dump(all_messages, outfile, ensure_ascii=False, cls=DateTimeEncoder)



@bot.on( events.NewMessage )
async def list( event ):
    match current_action:
        case '/tracking':
            channel = await client.get_entity( event.message.message )
            await dump_all_messages( channel )
            raise events.StopPropagation


@bot.on( events.NewMessage( pattern = '/tracking' ) )
async def link(event):
    global current_action
    current_action = '/tracking'
    await event.respond('I\'m expecting a link')
    raise events.StopPropagation

client.start()
bot.run_until_disconnected( )

为什么会发生这种情况（或者是在哪里发生问题是）？