How to use speech recognition module in python and use it in another program

Question

I have made a web browser by using python and I need to use speech recognition to control it (eg: open a tab, Close a tab, type Url)

import speech_recognition as sr
    
listener = sr.Recognizer()
    
class VoiceRecognition():
    
    def take_command(self):
        try:
             while True:
                with sr.Microphone() as source:
                    print('listening...')
                    voice = listener.listen(source)
                    command = listener.recognize_google(voice)
                    command = command.lower()
                    print(command)
    
        except:
            pass
        return command

This is the code for speech recognition

But when I use an object and call the take_command() function inside the web browser code it gives an error.

UnboundLocalError: local variable 'command' referenced before assignment

please help me.