How to add Hotword Detection in python AI

I am trying to make a python AI using the speech_recognition module, and i want to add a hotword detection feature in the AI, so I tried to make it using speech_recognition module but it didn't work. It listened once after 4 - 5 seconds and started recognizing the things spoken. Therefor if I speak the hotword after the 4-5 second timeframe, it doesn't recognize the hotword.

Use pause_threshold like

import speech_recognition as sr
hot_word='Hi'
r=sr.Recognizer()
r.pause_threshold=5#This waits for 5 sec after voice ends
with sr.Microphone() as source:
    text=r.listen(source)
text=r.recognize_google(text)
if hot_word in text:
    #do anything like calling a function or reply to it

Thank you
Have a good day