Python 3 script which permit to your bot to send messages in a group chat or a single person

send-telegram.py

#!/usr/bin/env python3

import urllib3
import certifi
import sys

# Generate a bot ID here: https://core.telegram.org/bots#botfather
bot_id = ''
chat_id = ''

if len(sys.argv) > 1:
    message = ''
    for word in sys.argv[1:]:
       message = message + ' ' + word
else:
    print('Sir, Where is the message?')
    print('./send-telegram-py write something')
    sys.exit()

try:
    https = urllib3.PoolManager(cert_reqs='CERT_REQUIRED', ca_certs=certifi.where())
    r = https.request('GET', 'https://api.telegram.org/bot' 
                    + bot_id + '/sendMessage?chat_id=' 
                    + chat_id + '&text=' + message)
except urllib3.exceptions.SSLError as err:
    print('[ERROR] Telegram SSL error', err)
    sys.exit()

Telegram Bot
First of all, you have to create a Bot and it's really simple: click here for the BotFather

Get a chat ID
Add your bot to a chat group and get updates of the bot for seeing the chatID, witht: 'https://api.telegram.org/bot' + bot_id + '/getUpdates'