recursion

import os

def get_factorial(n):
    # terminate function
    if n < 2:
        return n

    else: #recursion
        return n * get_factorial(n-1)

# print( get_factorial(7) )

# get all files in subfolders
def get_all_files(root_folder, file_list=[]):
    all_content = [os.path.join(root_folder, i) for i in os.listdir(root_folder)]

    # get files from current folder
    file_list += [i for i in all_content if os.path.isfile(i)]

    subfolders = [i for i in all_content if os.path.isdir(i)]

    for folder in subfolders:
        get_all_files(folder)

    return file_list


all_files = get_all_files(r"E:\Photos")
for i in all_files:
    print(i)