send message in channel with telethon code example
Example: telethon invite to group
# public chat
from telethon.tl.functions.channels import JoinChannelRequest
await client(JoinChannelRequest(channel))
# private chat
from telethon.tl.functions.messages import ImportChatInviteRequest
updates = await client(ImportChatInviteRequest('AAAAAEHbEkejzxUjAUCfYg'))