Modern Python implementation of a Telegram bot that only delivers messages

telegram_bot_echo.py

from os import environ
from typing import Dict
from typing import Optional
from typing import Tuple

from httpx import Client
from safe_assert import safe_assert as sassert


def _isnn(c):
    return c is not None

def emplace_kv(dictionary: dict, k, v) -> dict:
    return {**dictionary, k: v}


class TelegramBotEcho:  # NOSONAR
    __slots__: Tuple[str, str, str] = ("_url", "_jdata", "_client")

    def __init__(
        self,
        tok_var: Optional[str] = None,
        chid_var: Optional[str] = None,
        *,
        tok: Optional[str] = None,
        chid: Optional[str] = None,
    ) -> None:
        sassert(
            (_isnn(tok) ^ _isnn(tok_var)) and (_isnn(chid) ^ _isnn(chid_var)),
            "Exactly one among `tok` and `tok_var`, and exactly one among `chid` and `chid_var` must be defined.",
        )
        _tok: str = tok if _isnn(tok) else environ.get(tok_var)
        _chid: str = chid if _isnn(tok) else environ.get(chid_var)

        self._url: str = f"https://api.telegram.org/bot{_tok}/sendMessage"
        self._jdata: Dict[str, str] = {
            "chat_id": _chid,
            "text": "",
        }
        self._client = Client(http2=True)

    def send(self, msg: str) -> None:
        _ = self._client.post(url=self._url, json=emplace_kv(self._jdata, "text", msg))