@bot.message_handler(commands=['bc'])
def bc_msg(message):
  if message.from_user.id in ADMINS_IDS:
    if len(message.text.split()) < 2:
      bot.reply_to(message, "What should I broadcast?")
      return
    bcmsg = message.text.replace("/bc ","")
    allmembers = list(redisserver.smembers('zigzag_members'))
    for userid in allmembers:
      bot.send_message(userid, bcmsg, parse_mode="HTML")
    bot.reply_to(message, "Successfully broadcasted!")
  else:
    bot.send_message(message.chat.id, "You dont have permission.")

Create broadcast.py