xxxxxxxxxx
https://stackoverflow.com/questions/33858927/how-to-obtain-the-chat-id-of-a-private-telegram-channel/75456341#75456341
xxxxxxxxxx
1. open telegram Messanger
2. forward message from channel to this bot @JsonDumpBot
# return ex:
{
"date": 1640264623,
"forward_from_chat": {
"id": -1001707544375,
"title": "CHANNEL NAME",
"username": "YOUR_CHANNEL_USERNAME",
"type": "channel"
}