Ռեկուրսիա

def countdown(n):
    if n <= 0:
        # Base case: we've reached zero or below, so we stop
        print('Blastoff!')
    else:
        # Recursive case: print the current number and countdown from n-1
        print(n)
        countdown(n - 1)

def sum(n):
    print(f'sum() called with argument {n}')
    if n == 1:         # In case the given number is 1 => the sum is 1 as well
        return 1       # Return here and don't execute the following commands
    prev = sum(n - 1)  # Compute the sum for 1...(n-1)
    
    print(f'Adding current {n} to prev {prev}')
    return n + prev    # Return n + the sum for 1...(n-1)

print(sum(10))