Convert usd and eur in Bot Telegram – Telegram API

I’m studying Python for create a simple Bot for Telegram, but I have a problem. I created 2 files exchange.py and BotHtmlTelegram.py

exchange.py:

EXCHANGE=1.125

def from_usd_to_eur(usd):
    return usd/EXCHANGE

def from_eur_to_usd(eur):
    return EXCHANGE*eur

and this BotHtmlTelegram.py:

from telegram.ext import Updater, CommandHandler, MessageHandler, Filters
import exchange

TOKEN="My_Token"

def extract_number(text):
     return text.split()[1].strip()

def convert_usd(update, context):
     usd=float(extract_number(update.message.text))
     eur=exchange.from_usd_to_eur(usd)
     print(f'Eseguita conversione da {usd} USD a {eur} EUR')
     update.message.reply_text(f'{eur} EUR')

def convert_eur(update, context):
     eur=float(extract_number(update.message.text))
     usd=exchange.from_eur_to_usd(eur)
     print(f'Eseguita conversione da {eur} EUR a {usd} USD')
     update.message.reply_text(f'{usd} USD')

def main():
   upd= Updater("My_Token", use_context=True)
   disp=upd.dispatcher

   disp.add_handler(CommandHandler("usd", convert_usd))
   disp.add_handler(CommandHandler("eur", convert_eur))

   upd.start_polling()

   upd.idle()

if __name__=='__main__':
   main()

In my Bot Telegram I set command /eur and /usd – If I write /eur 100 the result it’s ok, but when I write /usr 100 nothing happens –

What am I doing wrong?

Thanks a lot mate