telegram_bot.py

from telegram import Update
from telegram.ext import ApplicationBuilder, CommandHandler, MessageHandler, filters, CallbackContext

def telebot():
    async def start(update: Update, context: CallbackContext) -> None:
        """Send a welcome message when the /start command is issued."""
        await update.message.reply_text('Hello! I am your bot. Send me any message and I will echo it back!')

    async def echo(update: Update, context: CallbackContext) -> None:
        """Echo the received message."""
        await update.message.reply_text(update.message.text)

    def main() -> None:
        app = ApplicationBuilder().token("7854626087:AAF5ls0oB8XR3SvQhWkxmea42e7FSf0yKTE").build()

        app.add_handler(CommandHandler("start", start))
        app.add_handler(MessageHandler(filters.TEXT & ~filters.COMMAND, echo))

        app.run_polling()
    main()

if __name__ == '__main__':
    telebot()