os module

import os

def folder_contains_extension(folder_path, extension):
    for file_name in os.listdir(folder_path):
        if file_name.endswith(extension):
            return True
    return False

# Test
folder_path = "/path/to/your/folder"
extension = ".txt"
print(folder_contains_extension(folder_path, extension))  # True or False

pathlib module

from pathlib import Path

def folder_contains_extension(folder_path, extension):
    folder = Path(folder_path)
    for file_path in folder.glob("*" + extension):
        return True
    return False

# Test
folder_path = "/path/to/your/folder"
extension = ".txt"
print(folder_contains_extension(folder_path, extension))  # True or False