How to Telegram auto Posting bot in Group?

i am searching for a solution. I hava a bot which post by /start command some stuff i need. But id like that the bot do this in a defined time, maybe every 6h.

Hope someone could help me.

import telegram
from telegram.ext import Updater
from telegram.ext import CommandHandler
from tracker import get_prices


telegram_bot_token = "xxx-xxx"

updater = Updater(token=telegram_bot_token, use_context=True)
dispatcher = updater.dispatcher


def start(update, context):
    chat_id = update.effective_chat.id
    message = ""

    crypto_data = get_prices()
    for i in crypto_data:
        coin = crypto_data[i]["coin"]
        price = crypto_data[i]["price"]
        change_day = crypto_data[i]["change_day"]
        change_hour = crypto_data[i]["change_hour"]
        message += f"Coin: {coin}\nPrice: ${price:,.2f}\nHour Change: {change_hour:.3f}%\nDay Change: {change_day:.3f}%\n\n"

    context.bot.send_message(chat_id=chat_id, text=message)


dispatcher.add_handler(CommandHandler("start", start))
updater.start_polling()

I was testing something an could add an timer, but is there a way to loop the programm with while True: ?

import telegram
from telegram.ext import Updater
from telegram.ext import CommandHandler
from tracker import get_prices
import threading
import time

telegram_bot_token = "xxx:xxx"

updater = Updater(token=telegram_bot_token, use_context=True)
dispatcher = updater.dispatcher

def message_timer(update, context):
    time.sleep(10)
    chat_id = update.effective_chat.id
    message = ""

    crypto_data = get_prices()
    for i in crypto_data:
        coin = crypto_data[i]["coin"]
        price = crypto_data[i]["price"]
        change_day = crypto_data[i]["change_day"]
        change_hour = crypto_data[i]["change_hour"]
        message += f"Coin: {coin}\nPrice: ${price:,.2f}\nHour Change: {change_hour:.3f}%\nDay Change: {change_day:.3f}%\n\n"

    context.bot.send_message(chat_id=chat_id, text=message)


dispatcher.add_handler(CommandHandler("start", message_timer))
updater.start_polling()